Merge #1297

1297: feat(stm32): Support multiple flash regions r=Dirbaio a=rmja

This depends on https://github.com/embassy-rs/stm32-data/pull/176

This is a general overhaul of the flash module to support multiple erase sizes.
Overall this PR contains:
* Move complex sector computation to embassy-hal-common to allow for tests
* Implement `FlashRegion` trait for each available flash region
* Add Flash::into_regions() to get each region.
* Implement embedded-storage traits for each region to support different erase sizes
* Split family write operations into begin/do/end
* Protection against simultaneous writes/erases for each split region is done through a global mutex

Co-authored-by: Rasmus Melchior Jacobsen <[email protected]>
Co-authored-by: Dario Nieuwenhuis <[email protected]>

20 files changed, 865 insertions, 423 deletions

diff --git a/ci.sh b/ci.sh
index d86c93520..b9dddad3a 100755
--- a/ci.sh
+++ b/ci.sh
@@ -49,6 +49,7 @@ cargo batch  \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32f411ce,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32f413vh,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32f429zi,log,exti,time-driver-any,unstable-traits,embedded-sdmmc \
+    --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32f730i8,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32h755zi-cm7,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32h7b3ai,defmt,exti,time-driver-any,unstable-traits \
     --- build --release --manifest-path embassy-stm32/Cargo.toml --target thumbv7em-none-eabi --features nightly,stm32l476vg,defmt,exti,time-driver-any,unstable-traits \
diff --git a/embassy-stm32/Cargo.toml b/embassy-stm32/Cargo.toml
index 14ec3d70a..504caacb2 100644
--- a/embassy-stm32/Cargo.toml
+++ b/embassy-stm32/Cargo.toml
@@ -60,7 +60,7 @@ sdio-host = "0.5.0"
 embedded-sdmmc = { git = "https://github.com/embassy-rs/embedded-sdmmc-rs", rev = "46d1b1c2ff13e31e282ec1e352421721694f126a", optional = true }
 critical-section = "1.1"
 atomic-polyfill = "1.0.1"
-stm32-metapac = { version = "2", features = ["rt"] }
+stm32-metapac = "3"
 vcell = "0.1.3"
 bxcan = "0.7.0"
 nb = "1.0.0"
@@ -69,12 +69,16 @@ seq-macro = "0.3.0"
 cfg-if = "1.0.0"
 embedded-io = { version = "0.4.0", features = ["async"], optional = true }
 
+[dev-dependencies]
+critical-section = { version = "1.1", features = ["std"] }
+
 [build-dependencies]
 proc-macro2 = "1.0.36"
 quote = "1.0.15"
-stm32-metapac = { version = "2", default-features = false, features = ["metadata"]}
+stm32-metapac = { version = "3", default-features = false, features = ["metadata"]}
 
 [features]
+default = ["stm32-metapac/rt"]
 defmt = ["dep:defmt", "bxcan/unstable-defmt", "embassy-sync/defmt", "embassy-executor/defmt", "embassy-embedded-hal/defmt", "embassy-hal-common/defmt", "embedded-io?/defmt", "embassy-usb-driver?/defmt", "embassy-net-driver/defmt"]
 memory-x = ["stm32-metapac/memory-x"]
 subghz = []
diff --git a/embassy-stm32/build.rs b/embassy-stm32/build.rs
index 481fec677..61aceed93 100644
--- a/embassy-stm32/build.rs
+++ b/embassy-stm32/build.rs
@@ -3,9 +3,9 @@ use std::fmt::Write as _;
 use std::path::PathBuf;
 use std::{env, fs};
 
-use proc_macro2::TokenStream;
+use proc_macro2::{Ident, TokenStream};
 use quote::{format_ident, quote};
-use stm32_metapac::metadata::METADATA;
+use stm32_metapac::metadata::{MemoryRegionKind, METADATA};
 
 fn main() {
     let chip_name = match env::vars()
@@ -107,6 +107,94 @@ fn main() {
     });
 
     // ========
+    // Generate FLASH regions
+    let mut flash_regions = TokenStream::new();
+    let flash_memory_regions: Vec<_> = METADATA
+        .memory
+        .iter()
+        .filter(|x| x.kind == MemoryRegionKind::Flash && x.settings.is_some())
+        .collect();
+    for region in flash_memory_regions.iter() {
+        let region_name = format_ident!("{}", get_flash_region_name(region.name));
+        let bank_variant = format_ident!(
+            "{}",
+            if region.name.starts_with("BANK_1") {
+                "Bank1"
+            } else if region.name.starts_with("BANK_2") {
+                "Bank2"
+            } else if region.name == "OTP" {
+                "Otp"
+            } else {
+                continue;
+            }
+        );
+        let base = region.address;
+        let size = region.size;
+        let settings = region.settings.as_ref().unwrap();
+        let erase_size = settings.erase_size;
+        let write_size = settings.write_size;
+        let erase_value = settings.erase_value;
+
+        flash_regions.extend(quote! {
+            pub const #region_name: crate::flash::FlashRegion = crate::flash::FlashRegion {
+                bank: crate::flash::FlashBank::#bank_variant,
+                base: #base,
+                size: #size,
+                erase_size: #erase_size,
+                write_size: #write_size,
+                erase_value: #erase_value,
+            };
+        });
+
+        let region_type = format_ident!("{}", get_flash_region_type_name(region.name));
+        flash_regions.extend(quote! {
+            #[cfg(flash)]
+            pub struct #region_type<'d>(pub &'static crate::flash::FlashRegion, pub(crate) embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>,);
+        });
+    }
+
+    let (fields, (inits, region_names)): (Vec<TokenStream>, (Vec<TokenStream>, Vec<Ident>)) = flash_memory_regions
+        .iter()
+        .map(|f| {
+            let region_name = get_flash_region_name(f.name);
+            let field_name = format_ident!("{}", region_name.to_lowercase());
+            let field_type = format_ident!("{}", get_flash_region_type_name(f.name));
+            let field = quote! {
+                pub #field_name: #field_type<'d>
+            };
+            let region_name = format_ident!("{}", region_name);
+            let init = quote! {
+                #field_name: #field_type(&#region_name, unsafe { p.clone_unchecked()})
+            };
+
+            (field, (init, region_name))
+        })
+        .unzip();
+
+    let regions_len = flash_memory_regions.len();
+    flash_regions.extend(quote! {
+        #[cfg(flash)]
+        pub struct FlashLayout<'d> {
+            #(#fields),*
+        }
+
+        #[cfg(flash)]
+        impl<'d> FlashLayout<'d> {
+            pub(crate) fn new(mut p: embassy_hal_common::PeripheralRef<'d, crate::peripherals::FLASH>) -> Self {
+                Self {
+                    #(#inits),*
+                }
+            }
+        }
+
+        pub const FLASH_REGIONS: [&crate::flash::FlashRegion; #regions_len] = [
+            #(&#region_names),*
+        ];
+    });
+
+    g.extend(quote! { pub mod flash_regions { #flash_regions } });
+
+    // ========
     // Generate DMA IRQs.
 
     let mut dma_irqs: HashMap<&str, Vec<(&str, &str)>> = HashMap::new();
@@ -578,11 +666,25 @@ fn main() {
     // ========
     // Write foreach_foo! macrotables
 
+    let mut flash_regions_table: Vec<Vec<String>> = Vec::new();
     let mut interrupts_table: Vec<Vec<String>> = Vec::new();
     let mut peripherals_table: Vec<Vec<String>> = Vec::new();
     let mut pins_table: Vec<Vec<String>> = Vec::new();
     let mut dma_channels_table: Vec<Vec<String>> = Vec::new();
 
+    for m in METADATA
+        .memory
+        .iter()
+        .filter(|m| m.kind == MemoryRegionKind::Flash && m.settings.is_some())
+    {
+        let settings = m.settings.as_ref().unwrap();
+        let mut row = Vec::new();
+        row.push(get_flash_region_type_name(m.name));
+        row.push(settings.write_size.to_string());
+        row.push(settings.erase_size.to_string());
+        flash_regions_table.push(row);
+    }
+
     let gpio_base = METADATA.peripherals.iter().find(|p| p.name == "GPIOA").unwrap().address as u32;
     let gpio_stride = 0x400;
 
@@ -679,6 +781,7 @@ fn main() {
 
     let mut m = String::new();
 
+    make_table(&mut m, "foreach_flash_region", &flash_regions_table);
     make_table(&mut m, "foreach_interrupt", &interrupts_table);
     make_table(&mut m, "foreach_peripheral", &peripherals_table);
     make_table(&mut m, "foreach_pin", &pins_table);
@@ -831,3 +934,19 @@ macro_rules! {} {{
     )
     .unwrap();
 }
+
+fn get_flash_region_name(name: &str) -> String {
+    let name = name.replace("BANK_", "BANK").replace("REGION_", "REGION");
+    if name.contains("REGION") {
+        name
+    } else {
+        name + "_REGION"
+    }
+}
+
+fn get_flash_region_type_name(name: &str) -> String {
+    get_flash_region_name(name)
+        .replace("BANK", "Bank")
+        .replace("REGION", "Region")
+        .replace("_", "")
+}
diff --git a/embassy-stm32/src/flash/common.rs b/embassy-stm32/src/flash/common.rs
new file mode 100644
index 000000000..8235d6f08
--- /dev/null
+++ b/embassy-stm32/src/flash/common.rs
@@ -0,0 +1,211 @@
+use atomic_polyfill::{fence, Ordering};
+use embassy_hal_common::drop::OnDrop;
+use embassy_hal_common::{into_ref, PeripheralRef};
+
+use super::{family, Error, FlashLayout, FlashRegion, FlashSector, FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
+use crate::flash::FlashBank;
+use crate::Peripheral;
+
+pub struct Flash<'d> {
+    inner: PeripheralRef<'d, crate::peripherals::FLASH>,
+}
+
+impl<'d> Flash<'d> {
+    pub fn new(p: impl Peripheral<P = crate::peripherals::FLASH> + 'd) -> Self {
+        into_ref!(p);
+        Self { inner: p }
+    }
+
+    pub fn into_regions(self) -> FlashLayout<'d> {
+        FlashLayout::new(self.release())
+    }
+
+    pub fn blocking_read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+        blocking_read(FLASH_BASE as u32, FLASH_SIZE as u32, offset, bytes)
+    }
+
+    pub fn blocking_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+        unsafe { blocking_write(FLASH_BASE as u32, FLASH_SIZE as u32, offset, bytes) }
+    }
+
+    pub fn blocking_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
+        unsafe { blocking_erase(FLASH_BASE as u32, from, to) }
+    }
+
+    pub(crate) fn release(self) -> PeripheralRef<'d, crate::peripherals::FLASH> {
+        let mut flash = self;
+        unsafe { flash.inner.clone_unchecked() }
+    }
+}
+
+fn blocking_read(base: u32, size: u32, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+    if offset + bytes.len() as u32 > size {
+        return Err(Error::Size);
+    }
+
+    let start_address = base + offset;
+    let flash_data = unsafe { core::slice::from_raw_parts(start_address as *const u8, bytes.len()) };
+    bytes.copy_from_slice(flash_data);
+    Ok(())
+}
+
+unsafe fn blocking_write(base: u32, size: u32, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+    if offset + bytes.len() as u32 > size {
+        return Err(Error::Size);
+    }
+    if offset % WRITE_SIZE as u32 != 0 || bytes.len() % WRITE_SIZE != 0 {
+        return Err(Error::Unaligned);
+    }
+
+    let mut address = base + offset;
+    trace!("Writing {} bytes at 0x{:x}", bytes.len(), address);
+
+    for chunk in bytes.chunks(WRITE_SIZE) {
+        critical_section::with(|_| {
+            family::clear_all_err();
+            fence(Ordering::SeqCst);
+            family::unlock();
+            fence(Ordering::SeqCst);
+            family::begin_write();
+            fence(Ordering::SeqCst);
+
+            let _on_drop = OnDrop::new(|| {
+                family::end_write();
+                fence(Ordering::SeqCst);
+                family::lock();
+            });
+
+            family::blocking_write(address, chunk.try_into().unwrap())
+        })?;
+        address += WRITE_SIZE as u32;
+    }
+    Ok(())
+}
+
+unsafe fn blocking_erase(base: u32, from: u32, to: u32) -> Result<(), Error> {
+    let start_address = base + from;
+    let end_address = base + to;
+    let regions = family::get_flash_regions();
+
+    // Test if the address range is aligned at sector base addresses
+    let mut address = start_address;
+    while address < end_address {
+        let sector = get_sector(address, regions);
+        if sector.start != address {
+            return Err(Error::Unaligned);
+        }
+        address += sector.size;
+    }
+    if address != end_address {
+        return Err(Error::Unaligned);
+    }
+
+    trace!("Erasing from 0x{:x} to 0x{:x}", start_address, end_address);
+
+    let mut address = start_address;
+    while address < end_address {
+        let sector = get_sector(address, regions);
+        trace!("Erasing sector: {:?}", sector);
+
+        critical_section::with(|_| {
+            family::clear_all_err();
+            fence(Ordering::SeqCst);
+            family::unlock();
+            fence(Ordering::SeqCst);
+
+            let _on_drop = OnDrop::new(|| {
+                family::lock();
+            });
+
+            family::blocking_erase_sector(&sector)
+        })?;
+        address += sector.size;
+    }
+    Ok(())
+}
+
+pub(crate) fn get_sector(address: u32, regions: &[&FlashRegion]) -> FlashSector {
+    let mut current_bank = FlashBank::Bank1;
+    let mut bank_offset = 0;
+    for region in regions {
+        if region.bank != current_bank {
+            current_bank = region.bank;
+            bank_offset = 0;
+        }
+
+        if address < region.end() {
+            let index_in_region = (address - region.base) / region.erase_size;
+            return FlashSector {
+                bank: region.bank,
+                index_in_bank: bank_offset + index_in_region as u8,
+                start: region.base + index_in_region * region.erase_size,
+                size: region.erase_size,
+            };
+        }
+
+        bank_offset += region.sectors();
+    }
+
+    panic!("Flash sector not found");
+}
+
+impl FlashRegion {
+    pub fn blocking_read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+        blocking_read(self.base, self.size, offset, bytes)
+    }
+
+    pub fn blocking_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+        unsafe { blocking_write(self.base, self.size, offset, bytes) }
+    }
+
+    pub fn blocking_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
+        unsafe { blocking_erase(self.base, from, to) }
+    }
+}
+
+foreach_flash_region! {
+    ($type_name:ident, $write_size:literal, $erase_size:literal) => {
+        impl crate::_generated::flash_regions::$type_name<'_> {
+            pub fn blocking_read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
+                blocking_read(self.0.base, self.0.size, offset, bytes)
+            }
+
+            pub fn blocking_write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Error> {
+                unsafe { blocking_write(self.0.base, self.0.size, offset, bytes) }
+            }
+
+            pub fn blocking_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
+                unsafe { blocking_erase(self.0.base, from, to) }
+            }
+        }
+
+        impl embedded_storage::nor_flash::ErrorType for crate::_generated::flash_regions::$type_name<'_> {
+            type Error = Error;
+        }
+
+        impl embedded_storage::nor_flash::ReadNorFlash for crate::_generated::flash_regions::$type_name<'_> {
+            const READ_SIZE: usize = 1;
+
+            fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
+                self.blocking_read(offset, bytes)
+            }
+
+            fn capacity(&self) -> usize {
+                self.0.size as usize
+            }
+        }
+
+        impl embedded_storage::nor_flash::NorFlash for crate::_generated::flash_regions::$type_name<'_> {
+            const WRITE_SIZE: usize = $write_size;
+            const ERASE_SIZE: usize = $erase_size;
+
+            fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
+                self.blocking_write(offset, bytes)
+            }
+
+            fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
+                self.blocking_erase(from, to)
+            }
+        }
+    };
+}
diff --git a/embassy-stm32/src/flash/f3.rs b/embassy-stm32/src/flash/f3.rs
index 1cb08ee1a..10a09c42c 100644
--- a/embassy-stm32/src/flash/f3.rs
+++ b/embassy-stm32/src/flash/f3.rs
@@ -1,9 +1,16 @@
 use core::convert::TryInto;
 use core::ptr::write_volatile;
 
+use atomic_polyfill::{fence, Ordering};
+
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
 use crate::flash::Error;
 use crate::pac;
 
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
 pub(crate) unsafe fn lock() {
     pac::FLASH.cr().modify(|w| w.set_lock(true));
 }
@@ -13,58 +20,55 @@ pub(crate) unsafe fn unlock() {
     pac::FLASH.keyr().write(|w| w.set_fkeyr(0xCDEF_89AB));
 }
 
-pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error> {
+pub(crate) unsafe fn begin_write() {
+    assert_eq!(0, WRITE_SIZE % 2);
+
     pac::FLASH.cr().write(|w| w.set_pg(true));
+}
 
-    let ret = {
-        let mut ret: Result<(), Error> = Ok(());
-        let mut offset = offset;
-        for chunk in buf.chunks(2) {
-            write_volatile(offset as *mut u16, u16::from_le_bytes(chunk[0..2].try_into().unwrap()));
-            offset += chunk.len() as u32;
+pub(crate) unsafe fn end_write() {
+    pac::FLASH.cr().write(|w| w.set_pg(false));
+}
 
-            ret = blocking_wait_ready();
-            if ret.is_err() {
-                break;
-            }
-        }
-        ret
-    };
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    let mut address = start_address;
+    for chunk in buf.chunks(2) {
+        write_volatile(address as *mut u16, u16::from_le_bytes(chunk.try_into().unwrap()));
+        address += chunk.len() as u32;
 
-    pac::FLASH.cr().write(|w| w.set_pg(false));
+        // prevents parallelism errors
+        fence(Ordering::SeqCst);
+    }
 
-    ret
+    blocking_wait_ready()
 }
 
-pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
-    for page in (from..to).step_by(super::ERASE_SIZE) {
-        pac::FLASH.cr().modify(|w| {
-            w.set_per(true);
-        });
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    pac::FLASH.cr().modify(|w| {
+        w.set_per(true);
+    });
 
-        pac::FLASH.ar().write(|w| w.set_far(page));
+    pac::FLASH.ar().write(|w| w.set_far(sector.start));
 
-        pac::FLASH.cr().modify(|w| {
-            w.set_strt(true);
-        });
+    pac::FLASH.cr().modify(|w| {
+        w.set_strt(true);
+    });
 
-        let mut ret: Result<(), Error> = blocking_wait_ready();
+    let mut ret: Result<(), Error> = blocking_wait_ready();
 
-        if !pac::FLASH.sr().read().eop() {
-            trace!("FLASH: EOP not set");
-            ret = Err(Error::Prog);
-        } else {
-            pac::FLASH.sr().write(|w| w.set_eop(true));
-        }
+    if !pac::FLASH.sr().read().eop() {
+        trace!("FLASH: EOP not set");
+        ret = Err(Error::Prog);
+    } else {
+        pac::FLASH.sr().write(|w| w.set_eop(true));
+    }
 
-        pac::FLASH.cr().modify(|w| w.set_per(false));
+    pac::FLASH.cr().modify(|w| w.set_per(false));
 
-        clear_all_err();
-        if ret.is_err() {
-            return ret;
-        }
+    clear_all_err();
+    if ret.is_err() {
+        return ret;
     }
-
     Ok(())
 }
 
@@ -82,7 +86,7 @@ pub(crate) unsafe fn clear_all_err() {
     });
 }
 
-pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
+unsafe fn blocking_wait_ready() -> Result<(), Error> {
     loop {
         let sr = pac::FLASH.sr().read();
 
diff --git a/embassy-stm32/src/flash/f4.rs b/embassy-stm32/src/flash/f4.rs
index 9e23a8adf..2ce9df69f 100644
--- a/embassy-stm32/src/flash/f4.rs
+++ b/embassy-stm32/src/flash/f4.rs
@@ -2,27 +2,108 @@ use core::convert::TryInto;
 use core::ptr::write_volatile;
 use core::sync::atomic::{fence, Ordering};
 
-use super::{ERASE_SIZE, FLASH_BASE, FLASH_SIZE};
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
 use crate::flash::Error;
 use crate::pac;
 
-const SECOND_BANK_SECTOR_START: u32 = 12;
+#[cfg(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479))]
+mod alt_regions {
+    use embassy_hal_common::PeripheralRef;
+    use stm32_metapac::FLASH_SIZE;
 
-unsafe fn is_dual_bank() -> bool {
-    match FLASH_SIZE / 1024 {
-        // 1 MB devices depend on configuration
-        1024 => {
-            if cfg!(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479)) {
-                pac::FLASH.optcr().read().db1m()
-            } else {
-                false
+    use crate::_generated::flash_regions::{BANK1_REGION1, BANK1_REGION2, BANK1_REGION3};
+    use crate::flash::{Bank1Region1, Bank1Region2, Flash, FlashBank, FlashRegion};
+    use crate::peripherals::FLASH;
+
+    pub const ALT_BANK1_REGION3: FlashRegion = FlashRegion {
+        size: 3 * BANK1_REGION3.erase_size,
+        ..BANK1_REGION3
+    };
+    pub const ALT_BANK2_REGION1: FlashRegion = FlashRegion {
+        bank: FlashBank::Bank2,
+        base: BANK1_REGION1.base + FLASH_SIZE as u32 / 2,
+        ..BANK1_REGION1
+    };
+    pub const ALT_BANK2_REGION2: FlashRegion = FlashRegion {
+        bank: FlashBank::Bank2,
+        base: BANK1_REGION2.base + FLASH_SIZE as u32 / 2,
+        ..BANK1_REGION2
+    };
+    pub const ALT_BANK2_REGION3: FlashRegion = FlashRegion {
+        bank: FlashBank::Bank2,
+        base: BANK1_REGION3.base + FLASH_SIZE as u32 / 2,
+        size: 3 * BANK1_REGION3.erase_size,
+        ..BANK1_REGION3
+    };
+
+    pub const ALT_FLASH_REGIONS: [&FlashRegion; 6] = [
+        &BANK1_REGION1,
+        &BANK1_REGION2,
+        &ALT_BANK1_REGION3,
+        &ALT_BANK2_REGION1,
+        &ALT_BANK2_REGION2,
+        &ALT_BANK2_REGION3,
+    ];
+
+    pub type AltBank1Region1<'d> = Bank1Region1<'d>;
+    pub type AltBank1Region2<'d> = Bank1Region2<'d>;
+    pub struct AltBank1Region3<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region1<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region2<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+    pub struct AltBank2Region3<'d>(pub &'static FlashRegion, PeripheralRef<'d, FLASH>);
+
+    pub struct AltFlashLayout<'d> {
+        pub bank1_region1: AltBank1Region1<'d>,
+        pub bank1_region2: AltBank1Region2<'d>,
+        pub bank1_region3: AltBank1Region3<'d>,
+        pub bank2_region1: AltBank2Region1<'d>,
+        pub bank2_region2: AltBank2Region2<'d>,
+        pub bank2_region3: AltBank2Region3<'d>,
+    }
+
+    impl<'d> Flash<'d> {
+        pub fn into_alt_regions(self) -> AltFlashLayout<'d> {
+            unsafe { crate::pac::FLASH.optcr().modify(|r| r.set_db1m(true)) };
+
+            // SAFETY: We never expose the cloned peripheral references, and their instance is not public.
+            // Also, all flash region operations are protected with a cs.
+            let mut p = self.release();
+            AltFlashLayout {
+                bank1_region1: Bank1Region1(&BANK1_REGION1, unsafe { p.clone_unchecked() }),
+                bank1_region2: Bank1Region2(&BANK1_REGION2, unsafe { p.clone_unchecked() }),
+                bank1_region3: AltBank1Region3(&ALT_BANK1_REGION3, unsafe { p.clone_unchecked() }),
+                bank2_region1: AltBank2Region1(&ALT_BANK2_REGION1, unsafe { p.clone_unchecked() }),
+                bank2_region2: AltBank2Region2(&ALT_BANK2_REGION2, unsafe { p.clone_unchecked() }),
+                bank2_region3: AltBank2Region3(&ALT_BANK2_REGION3, unsafe { p.clone_unchecked() }),
             }
         }
-        // 2 MB devices are always dual bank
-        2048 => true,
-        // All other devices are single bank
-        _ => false,
     }
+
+    impl Drop for AltFlashLayout<'_> {
+        fn drop(&mut self) {
+            unsafe {
+                super::lock();
+                crate::pac::FLASH.optcr().modify(|r| r.set_db1m(false))
+            };
+        }
+    }
+}
+
+#[cfg(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479))]
+pub use alt_regions::{AltFlashLayout, ALT_FLASH_REGIONS};
+
+#[cfg(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479))]
+pub fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    if unsafe { pac::FLASH.optcr().read().db1m() } {
+        &ALT_FLASH_REGIONS
+    } else {
+        &FLASH_REGIONS
+    }
+}
+
+#[cfg(not(any(stm32f427, stm32f429, stm32f437, stm32f439, stm32f469, stm32f479)))]
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
 }
 
 pub(crate) unsafe fn lock() {
@@ -34,93 +115,34 @@ pub(crate) unsafe fn unlock() {
     pac::FLASH.keyr().write(|w| w.set_key(0xCDEF_89AB));
 }
 
-pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error> {
+pub(crate) unsafe fn begin_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+
     pac::FLASH.cr().write(|w| {
         w.set_pg(true);
         w.set_psize(pac::flash::vals::Psize::PSIZE32);
     });
-
-    let ret = {
-        let mut ret: Result<(), Error> = Ok(());
-        let mut offset = offset;
-        for chunk in buf.chunks(super::WRITE_SIZE) {
-            for val in chunk.chunks(4) {
-                write_volatile(offset as *mut u32, u32::from_le_bytes(val[0..4].try_into().unwrap()));
-                offset += val.len() as u32;
-
-                // prevents parallelism errors
-                fence(Ordering::SeqCst);
-            }
-
-            ret = blocking_wait_ready();
-            if ret.is_err() {
-                break;
-            }
-        }
-        ret
-    };
-
-    pac::FLASH.cr().write(|w| w.set_pg(false));
-
-    ret
 }
 
-struct FlashSector {
-    index: u8,
-    size: u32,
-}
-
-fn get_sector(addr: u32, dual_bank: bool) -> FlashSector {
-    let offset = addr - FLASH_BASE as u32;
-
-    let bank_size = match dual_bank {
-        true => FLASH_SIZE / 2,
-        false => FLASH_SIZE,
-    } as u32;
-
-    let bank = offset / bank_size;
-    let offset_in_bank = offset % bank_size;
-
-    let index_in_bank = if offset_in_bank >= ERASE_SIZE as u32 / 2 {
-        4 + offset_in_bank / ERASE_SIZE as u32
-    } else {
-        offset_in_bank / (ERASE_SIZE as u32 / 8)
-    };
-
-    // First 4 sectors are 16KB, then one 64KB, and rest are 128KB
-    let size = match index_in_bank {
-        0..=3 => 16 * 1024,
-        4 => 64 * 1024,
-        _ => 128 * 1024,
-    };
-
-    let index = if bank == 1 {
-        SECOND_BANK_SECTOR_START + index_in_bank
-    } else {
-        index_in_bank
-    } as u8;
-
-    FlashSector { index, size }
+pub(crate) unsafe fn end_write() {
+    pac::FLASH.cr().write(|w| w.set_pg(false));
 }
 
-pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
-    let mut addr = from;
-    let dual_bank = is_dual_bank();
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    let mut address = start_address;
+    for val in buf.chunks(4) {
+        write_volatile(address as *mut u32, u32::from_le_bytes(val.try_into().unwrap()));
+        address += val.len() as u32;
 
-    while addr < to {
-        let sector = get_sector(addr, dual_bank);
-        erase_sector(sector.index)?;
-        addr += sector.size;
+        // prevents parallelism errors
+        fence(Ordering::SeqCst);
     }
 
-    Ok(())
+    blocking_wait_ready()
 }
 
-unsafe fn erase_sector(sector: u8) -> Result<(), Error> {
-    let bank = sector / SECOND_BANK_SECTOR_START as u8;
-    let snb = (bank << 4) + (sector % SECOND_BANK_SECTOR_START as u8);
-
-    trace!("Erasing sector: {}", sector);
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    let snb = ((sector.bank as u8) << 4) + sector.index_in_bank;
 
     pac::FLASH.cr().modify(|w| {
         w.set_ser(true);
@@ -148,7 +170,7 @@ pub(crate) unsafe fn clear_all_err() {
     });
 }
 
-pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
+unsafe fn blocking_wait_ready() -> Result<(), Error> {
     loop {
         let sr = pac::FLASH.sr().read();
 
@@ -173,3 +195,80 @@ pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::flash::{get_sector, FlashBank};
+
+    #[test]
+    #[cfg(stm32f429)]
+    fn can_get_sector_single_bank() {
+        const SMALL_SECTOR_SIZE: u32 = 16 * 1024;
+        const MEDIUM_SECTOR_SIZE: u32 = 64 * 1024;
+        const LARGE_SECTOR_SIZE: u32 = 128 * 1024;
+
+        let assert_sector = |index_in_bank: u8, start: u32, size: u32, address: u32| {
+            assert_eq!(
+                FlashSector {
+                    bank: FlashBank::Bank1,
+                    index_in_bank,
+                    start,
+                    size
+                },
+                get_sector(address, &FLASH_REGIONS)
+            )
+        };
+
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_0000);
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_3FFF);
+        assert_sector(3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_C000);
+        assert_sector(3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_FFFF);
+
+        assert_sector(4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_0000);
+        assert_sector(4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_FFFF);
+
+        assert_sector(5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0802_0000);
+        assert_sector(5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0803_FFFF);
+        assert_sector(11, 0x080E_0000, LARGE_SECTOR_SIZE, 0x080E_0000);
+        assert_sector(11, 0x080E_0000, LARGE_SECTOR_SIZE, 0x080F_FFFF);
+
+        let assert_sector = |bank: FlashBank, index_in_bank: u8, start: u32, size: u32, address: u32| {
+            assert_eq!(
+                FlashSector {
+                    bank,
+                    index_in_bank,
+                    start,
+                    size
+                },
+                get_sector(address, &ALT_FLASH_REGIONS)
+            )
+        };
+
+        assert_sector(FlashBank::Bank1, 0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_0000);
+        assert_sector(FlashBank::Bank1, 0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_3FFF);
+        assert_sector(FlashBank::Bank1, 3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_C000);
+        assert_sector(FlashBank::Bank1, 3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_FFFF);
+
+        assert_sector(FlashBank::Bank1, 4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_0000);
+        assert_sector(FlashBank::Bank1, 4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_FFFF);
+
+        assert_sector(FlashBank::Bank1, 5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0802_0000);
+        assert_sector(FlashBank::Bank1, 5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0803_FFFF);
+        assert_sector(FlashBank::Bank1, 7, 0x0806_0000, LARGE_SECTOR_SIZE, 0x0806_0000);
+        assert_sector(FlashBank::Bank1, 7, 0x0806_0000, LARGE_SECTOR_SIZE, 0x0807_FFFF);
+
+        assert_sector(FlashBank::Bank2, 0, 0x0808_0000, SMALL_SECTOR_SIZE, 0x0808_0000);
+        assert_sector(FlashBank::Bank2, 0, 0x0808_0000, SMALL_SECTOR_SIZE, 0x0808_3FFF);
+        assert_sector(FlashBank::Bank2, 3, 0x0808_C000, SMALL_SECTOR_SIZE, 0x0808_C000);
+        assert_sector(FlashBank::Bank2, 3, 0x0808_C000, SMALL_SECTOR_SIZE, 0x0808_FFFF);
+
+        assert_sector(FlashBank::Bank2, 4, 0x0809_0000, MEDIUM_SECTOR_SIZE, 0x0809_0000);
+        assert_sector(FlashBank::Bank2, 4, 0x0809_0000, MEDIUM_SECTOR_SIZE, 0x0809_FFFF);
+
+        assert_sector(FlashBank::Bank2, 5, 0x080A_0000, LARGE_SECTOR_SIZE, 0x080A_0000);
+        assert_sector(FlashBank::Bank2, 5, 0x080A_0000, LARGE_SECTOR_SIZE, 0x080B_FFFF);
+        assert_sector(FlashBank::Bank2, 7, 0x080E_0000, LARGE_SECTOR_SIZE, 0x080E_0000);
+        assert_sector(FlashBank::Bank2, 7, 0x080E_0000, LARGE_SECTOR_SIZE, 0x080F_FFFF);
+    }
+}
diff --git a/embassy-stm32/src/flash/f7.rs b/embassy-stm32/src/flash/f7.rs
index dd0d8439d..6427d5a09 100644
--- a/embassy-stm32/src/flash/f7.rs
+++ b/embassy-stm32/src/flash/f7.rs
@@ -2,9 +2,14 @@ use core::convert::TryInto;
 use core::ptr::write_volatile;
 use core::sync::atomic::{fence, Ordering};
 
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
 use crate::flash::Error;
 use crate::pac;
 
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
 pub(crate) unsafe fn lock() {
     pac::FLASH.cr().modify(|w| w.set_lock(true));
 }
@@ -14,64 +19,36 @@ pub(crate) unsafe fn unlock() {
     pac::FLASH.keyr().write(|w| w.set_key(0xCDEF_89AB));
 }
 
-pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error> {
+pub(crate) unsafe fn begin_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+
     pac::FLASH.cr().write(|w| {
         w.set_pg(true);
         w.set_psize(pac::flash::vals::Psize::PSIZE32);
     });
+}
 
-    let ret = {
-        let mut ret: Result<(), Error> = Ok(());
-        let mut offset = offset;
-        for chunk in buf.chunks(super::WRITE_SIZE) {
-            for val in chunk.chunks(4) {
-                write_volatile(offset as *mut u32, u32::from_le_bytes(val[0..4].try_into().unwrap()));
-                offset += val.len() as u32;
-
-                // prevents parallelism errors
-                fence(Ordering::SeqCst);
-            }
-
-            ret = blocking_wait_ready();
-            if ret.is_err() {
-                break;
-            }
-        }
-        ret
-    };
-
+pub(crate) unsafe fn end_write() {
     pac::FLASH.cr().write(|w| w.set_pg(false));
-
-    ret
 }
 
-pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
-    let start_sector = if from >= (super::FLASH_BASE + super::ERASE_SIZE / 2) as u32 {
-        4 + (from - super::FLASH_BASE as u32) / super::ERASE_SIZE as u32
-    } else {
-        (from - super::FLASH_BASE as u32) / (super::ERASE_SIZE as u32 / 8)
-    };
-
-    let end_sector = if to >= (super::FLASH_BASE + super::ERASE_SIZE / 2) as u32 {
-        4 + (to - super::FLASH_BASE as u32) / super::ERASE_SIZE as u32
-    } else {
-        (to - super::FLASH_BASE as u32) / (super::ERASE_SIZE as u32 / 8)
-    };
-
-    for sector in start_sector..end_sector {
-        let ret = erase_sector(sector as u8);
-        if ret.is_err() {
-            return ret;
-        }
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    let mut address = start_address;
+    for val in buf.chunks(4) {
+        write_volatile(address as *mut u32, u32::from_le_bytes(val.try_into().unwrap()));
+        address += val.len() as u32;
+
+        // prevents parallelism errors
+        fence(Ordering::SeqCst);
     }
 
-    Ok(())
+    blocking_wait_ready()
 }
 
-unsafe fn erase_sector(sector: u8) -> Result<(), Error> {
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
     pac::FLASH.cr().modify(|w| {
         w.set_ser(true);
-        w.set_snb(sector)
+        w.set_snb(sector.index_in_bank)
     });
 
     pac::FLASH.cr().modify(|w| {
@@ -107,7 +84,7 @@ pub(crate) unsafe fn clear_all_err() {
     });
 }
 
-pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
+unsafe fn blocking_wait_ready() -> Result<(), Error> {
     loop {
         let sr = pac::FLASH.sr().read();
 
@@ -132,3 +109,75 @@ pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
         }
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::flash::{get_sector, FlashBank};
+
+    #[test]
+    #[cfg(stm32f732)]
+    fn can_get_sector() {
+        const SMALL_SECTOR_SIZE: u32 = 16 * 1024;
+        const MEDIUM_SECTOR_SIZE: u32 = 64 * 1024;
+        const LARGE_SECTOR_SIZE: u32 = 128 * 1024;
+
+        let assert_sector = |index_in_bank: u8, start: u32, size: u32, address: u32| {
+            assert_eq!(
+                FlashSector {
+                    bank: FlashBank::Bank1,
+                    index_in_bank,
+                    start,
+                    size
+                },
+                get_sector(address, &FLASH_REGIONS)
+            )
+        };
+
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_0000);
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_3FFF);
+        assert_sector(3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_C000);
+        assert_sector(3, 0x0800_C000, SMALL_SECTOR_SIZE, 0x0800_FFFF);
+
+        assert_sector(4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_0000);
+        assert_sector(4, 0x0801_0000, MEDIUM_SECTOR_SIZE, 0x0801_FFFF);
+
+        assert_sector(5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0802_0000);
+        assert_sector(5, 0x0802_0000, LARGE_SECTOR_SIZE, 0x0803_FFFF);
+        assert_sector(7, 0x0806_0000, LARGE_SECTOR_SIZE, 0x0806_0000);
+        assert_sector(7, 0x0806_0000, LARGE_SECTOR_SIZE, 0x0807_FFFF);
+    }
+
+    #[test]
+    #[cfg(stm32f769)]
+    fn can_get_sector() {
+        const SMALL_SECTOR_SIZE: u32 = 32 * 1024;
+        const MEDIUM_SECTOR_SIZE: u32 = 128 * 1024;
+        const LARGE_SECTOR_SIZE: u32 = 256 * 1024;
+
+        let assert_sector = |index_in_bank: u8, start: u32, size: u32, address: u32| {
+            assert_eq!(
+                FlashSector {
+                    bank: FlashBank::Bank1,
+                    index_in_bank,
+                    start,
+                    size
+                },
+                get_sector(address, &FLASH_REGIONS)
+            )
+        };
+
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_0000);
+        assert_sector(0, 0x0800_0000, SMALL_SECTOR_SIZE, 0x0800_7FFF);
+        assert_sector(3, 0x0801_8000, SMALL_SECTOR_SIZE, 0x0801_8000);
+        assert_sector(3, 0x0801_8000, SMALL_SECTOR_SIZE, 0x0801_FFFF);
+
+        assert_sector(4, 0x0802_0000, MEDIUM_SECTOR_SIZE, 0x0802_0000);
+        assert_sector(4, 0x0802_0000, MEDIUM_SECTOR_SIZE, 0x0803_FFFF);
+
+        assert_sector(5, 0x0804_0000, LARGE_SECTOR_SIZE, 0x0804_0000);
+        assert_sector(5, 0x0804_0000, LARGE_SECTOR_SIZE, 0x0807_FFFF);
+        assert_sector(7, 0x080C_0000, LARGE_SECTOR_SIZE, 0x080C_0000);
+        assert_sector(7, 0x080C_0000, LARGE_SECTOR_SIZE, 0x080F_FFFF);
+    }
+}
diff --git a/embassy-stm32/src/flash/h7.rs b/embassy-stm32/src/flash/h7.rs
index 7de95ac11..4f38d50c0 100644
--- a/embassy-stm32/src/flash/h7.rs
+++ b/embassy-stm32/src/flash/h7.rs
@@ -1,13 +1,18 @@
 use core::convert::TryInto;
 use core::ptr::write_volatile;
 
+use atomic_polyfill::{fence, Ordering};
+
+use super::{FlashRegion, FlashSector, BANK1_REGION, FLASH_REGIONS, WRITE_SIZE};
 use crate::flash::Error;
 use crate::pac;
 
-const SECOND_BANK_OFFSET: usize = 0x0010_0000;
-
 const fn is_dual_bank() -> bool {
-    super::FLASH_SIZE / 2 > super::ERASE_SIZE
+    FLASH_REGIONS.len() == 2
+}
+
+pub fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
 }
 
 pub(crate) unsafe fn lock() {
@@ -20,90 +25,64 @@ pub(crate) unsafe fn lock() {
 pub(crate) unsafe fn unlock() {
     pac::FLASH.bank(0).keyr().write(|w| w.set_keyr(0x4567_0123));
     pac::FLASH.bank(0).keyr().write(|w| w.set_keyr(0xCDEF_89AB));
-
     if is_dual_bank() {
         pac::FLASH.bank(1).keyr().write(|w| w.set_keyr(0x4567_0123));
         pac::FLASH.bank(1).keyr().write(|w| w.set_keyr(0xCDEF_89AB));
     }
 }
 
-pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error> {
-    let bank = if !is_dual_bank() || (offset - super::FLASH_BASE as u32) < SECOND_BANK_OFFSET as u32 {
+pub(crate) unsafe fn begin_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+}
+
+pub(crate) unsafe fn end_write() {}
+
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    // We cannot have the write setup sequence in begin_write as it depends on the address
+    let bank = if start_address < BANK1_REGION.end() {
         pac::FLASH.bank(0)
     } else {
         pac::FLASH.bank(1)
     };
-
     bank.cr().write(|w| {
         w.set_pg(true);
         w.set_psize(2); // 32 bits at once
     });
-
     cortex_m::asm::isb();
     cortex_m::asm::dsb();
-    core::sync::atomic::fence(core::sync::atomic::Ordering::SeqCst);
-
-    let ret = {
-        let mut ret: Result<(), Error> = Ok(());
-        let mut offset = offset;
-        'outer: for chunk in buf.chunks(super::WRITE_SIZE) {
-            for val in chunk.chunks(4) {
-                trace!("Writing at {:x}", offset);
-                write_volatile(offset as *mut u32, u32::from_le_bytes(val[0..4].try_into().unwrap()));
-                offset += val.len() as u32;
-
-                ret = blocking_wait_ready(bank);
-                bank.sr().modify(|w| {
-                    if w.eop() {
-                        w.set_eop(true);
-                    }
-                });
-                if ret.is_err() {
-                    break 'outer;
-                }
+    fence(Ordering::SeqCst);
+
+    let mut res = None;
+    let mut address = start_address;
+    for val in buf.chunks(4) {
+        write_volatile(address as *mut u32, u32::from_le_bytes(val.try_into().unwrap()));
+        address += val.len() as u32;
+
+        res = Some(blocking_wait_ready(bank));
+        bank.sr().modify(|w| {
+            if w.eop() {
+                w.set_eop(true);
             }
+        });
+        if res.unwrap().is_err() {
+            break;
         }
-        ret
-    };
+    }
 
     bank.cr().write(|w| w.set_pg(false));
 
     cortex_m::asm::isb();
     cortex_m::asm::dsb();
-    core::sync::atomic::fence(core::sync::atomic::Ordering::SeqCst);
-
-    ret
-}
-
-pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
-    let from = from - super::FLASH_BASE as u32;
-    let to = to - super::FLASH_BASE as u32;
-
-    let (start, end) = if to <= super::FLASH_SIZE as u32 {
-        let start_sector = from / super::ERASE_SIZE as u32;
-        let end_sector = to / super::ERASE_SIZE as u32;
-        (start_sector, end_sector)
-    } else {
-        error!("Attempting to write outside of defined sectors {:x} {:x}", from, to);
-        return Err(Error::Unaligned);
-    };
-
-    trace!("Erasing sectors from {} to {}", start, end);
-    for sector in start..end {
-        let bank = if sector >= 8 { 1 } else { 0 };
-        let ret = erase_sector(pac::FLASH.bank(bank), (sector % 8) as u8);
-        if ret.is_err() {
-            return ret;
-        }
-    }
+    fence(Ordering::SeqCst);
 
-    Ok(())
+    res.unwrap()
 }
 
-unsafe fn erase_sector(bank: pac::flash::Bank, sector: u8) -> Result<(), Error> {
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    let bank = pac::FLASH.bank(sector.bank as usize);
     bank.cr().modify(|w| {
         w.set_ser(true);
-        w.set_snb(sector)
+        w.set_snb(sector.index_in_bank)
     });
 
     bank.cr().modify(|w| {
@@ -160,7 +139,7 @@ unsafe fn bank_clear_all_err(bank: pac::flash::Bank) {
     });
 }
 
-pub(crate) unsafe fn blocking_wait_ready(bank: pac::flash::Bank) -> Result<(), Error> {
+unsafe fn blocking_wait_ready(bank: pac::flash::Bank) -> Result<(), Error> {
     loop {
         let sr = bank.sr().read();
 
diff --git a/embassy-stm32/src/flash/l.rs b/embassy-stm32/src/flash/l.rs
index 5048a3314..7d9cc6ea3 100644
--- a/embassy-stm32/src/flash/l.rs
+++ b/embassy-stm32/src/flash/l.rs
@@ -1,9 +1,15 @@
-use core::convert::TryInto;
 use core::ptr::write_volatile;
 
+use atomic_polyfill::{fence, Ordering};
+
+use super::{FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
 use crate::flash::Error;
 use crate::pac;
 
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
 pub(crate) unsafe fn lock() {
     #[cfg(any(flash_wl, flash_wb, flash_l4))]
     pac::FLASH.cr().modify(|w| w.set_lock(true));
@@ -33,82 +39,75 @@ pub(crate) unsafe fn unlock() {
     }
 }
 
-pub(crate) unsafe fn blocking_write(offset: u32, buf: &[u8]) -> Result<(), Error> {
+pub(crate) unsafe fn begin_write() {
+    assert_eq!(0, WRITE_SIZE % 4);
+
     #[cfg(any(flash_wl, flash_wb, flash_l4))]
     pac::FLASH.cr().write(|w| w.set_pg(true));
+}
 
-    let ret = {
-        let mut ret: Result<(), Error> = Ok(());
-        let mut offset = offset;
-        for chunk in buf.chunks(super::WRITE_SIZE) {
-            for val in chunk.chunks(4) {
-                write_volatile(offset as *mut u32, u32::from_le_bytes(val[0..4].try_into().unwrap()));
-                offset += val.len() as u32;
-            }
-
-            ret = blocking_wait_ready();
-            if ret.is_err() {
-                break;
-            }
-        }
-        ret
-    };
-
+pub(crate) unsafe fn end_write() {
     #[cfg(any(flash_wl, flash_wb, flash_l4))]
     pac::FLASH.cr().write(|w| w.set_pg(false));
-
-    ret
 }
 
-pub(crate) unsafe fn blocking_erase(from: u32, to: u32) -> Result<(), Error> {
-    for page in (from..to).step_by(super::ERASE_SIZE) {
-        #[cfg(any(flash_l0, flash_l1))]
-        {
-            pac::FLASH.pecr().modify(|w| {
-                w.set_erase(true);
-                w.set_prog(true);
-            });
+pub(crate) unsafe fn blocking_write(start_address: u32, buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    let mut address = start_address;
+    for val in buf.chunks(4) {
+        write_volatile(address as *mut u32, u32::from_le_bytes(val.try_into().unwrap()));
+        address += val.len() as u32;
 
-            write_volatile(page as *mut u32, 0xFFFFFFFF);
-        }
-
-        #[cfg(any(flash_wl, flash_wb, flash_l4))]
-        {
-            let idx = (page - super::FLASH_BASE as u32) / super::ERASE_SIZE as u32;
-
-            #[cfg(flash_l4)]
-            let (idx, bank) = if idx > 255 { (idx - 256, true) } else { (idx, false) };
-
-            pac::FLASH.cr().modify(|w| {
-                w.set_per(true);
-                w.set_pnb(idx as u8);
-                #[cfg(any(flash_wl, flash_wb))]
-                w.set_strt(true);
-                #[cfg(any(flash_l4))]
-                w.set_start(true);
-                #[cfg(any(flash_l4))]
-                w.set_bker(bank);
-            });
-        }
-
-        let ret: Result<(), Error> = blocking_wait_ready();
+        // prevents parallelism errors
+        fence(Ordering::SeqCst);
+    }
 
-        #[cfg(any(flash_wl, flash_wb, flash_l4))]
-        pac::FLASH.cr().modify(|w| w.set_per(false));
+    blocking_wait_ready()
+}
 
-        #[cfg(any(flash_l0, flash_l1))]
+pub(crate) unsafe fn blocking_erase_sector(sector: &FlashSector) -> Result<(), Error> {
+    #[cfg(any(flash_l0, flash_l1))]
+    {
         pac::FLASH.pecr().modify(|w| {
-            w.set_erase(false);
-            w.set_prog(false);
+            w.set_erase(true);
+            w.set_prog(true);
         });
 
-        clear_all_err();
-        if ret.is_err() {
-            return ret;
-        }
+        write_volatile(sector.start as *mut u32, 0xFFFFFFFF);
+    }
+
+    #[cfg(any(flash_wl, flash_wb, flash_l4))]
+    {
+        let idx = (sector.start - super::FLASH_BASE as u32) / super::BANK1_REGION.erase_size as u32;
+
+        #[cfg(flash_l4)]
+        let (idx, bank) = if idx > 255 { (idx - 256, true) } else { (idx, false) };
+
+        pac::FLASH.cr().modify(|w| {
+            w.set_per(true);
+            w.set_pnb(idx as u8);
+            #[cfg(any(flash_wl, flash_wb))]
+            w.set_strt(true);
+            #[cfg(any(flash_l4))]
+            w.set_start(true);
+            #[cfg(any(flash_l4))]
+            w.set_bker(bank);
+        });
     }
 
-    Ok(())
+    let ret: Result<(), Error> = blocking_wait_ready();
+
+    #[cfg(any(flash_wl, flash_wb, flash_l4))]
+    pac::FLASH.cr().modify(|w| w.set_per(false));
+
+    #[cfg(any(flash_l0, flash_l1))]
+    pac::FLASH.pecr().modify(|w| {
+        w.set_erase(false);
+        w.set_prog(false);
+    });
+
+    clear_all_err();
+
+    ret
 }
 
 pub(crate) unsafe fn clear_all_err() {
@@ -149,7 +148,7 @@ pub(crate) unsafe fn clear_all_err() {
     });
 }
 
-pub(crate) unsafe fn blocking_wait_ready() -> Result<(), Error> {
+unsafe fn blocking_wait_ready() -> Result<(), Error> {
     loop {
         let sr = pac::FLASH.sr().read();
 
diff --git a/embassy-stm32/src/flash/mod.rs b/embassy-stm32/src/flash/mod.rs
index b7166a437..231ff1f9e 100644
--- a/embassy-stm32/src/flash/mod.rs
+++ b/embassy-stm32/src/flash/mod.rs
@@ -1,89 +1,67 @@
-use embassy_hal_common::{into_ref, PeripheralRef};
-use embedded_storage::nor_flash::{ErrorType, NorFlash, NorFlashError, NorFlashErrorKind, ReadNorFlash};
+use embedded_storage::nor_flash::{NorFlashError, NorFlashErrorKind};
 
-pub use crate::pac::{ERASE_SIZE, ERASE_VALUE, FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
-use crate::peripherals::FLASH;
-use crate::Peripheral;
-const FLASH_END: usize = FLASH_BASE + FLASH_SIZE;
+#[cfg(flash)]
+mod common;
 
-#[cfg_attr(any(flash_wl, flash_wb, flash_l0, flash_l1, flash_l4), path = "l.rs")]
-#[cfg_attr(flash_f3, path = "f3.rs")]
-#[cfg_attr(flash_f4, path = "f4.rs")]
-#[cfg_attr(flash_f7, path = "f7.rs")]
-#[cfg_attr(flash_h7, path = "h7.rs")]
-mod family;
+#[cfg(flash)]
+pub use common::*;
 
-pub struct Flash<'d> {
-    _inner: PeripheralRef<'d, FLASH>,
-}
+pub use crate::_generated::flash_regions::*;
+pub use crate::pac::{FLASH_BASE, FLASH_SIZE, WRITE_SIZE};
 
-impl<'d> Flash<'d> {
-    pub fn new(p: impl Peripheral<P = FLASH> + 'd) -> Self {
-        into_ref!(p);
-        Self { _inner: p }
-    }
-
-    pub fn blocking_read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Error> {
-        let offset = FLASH_BASE as u32 + offset;
-        if offset as usize >= FLASH_END || offset as usize + bytes.len() > FLASH_END {
-            return Err(Error::Size);
-        }
-
-        let flash_data = unsafe { core::slice::from_raw_parts(offset as *const u8, bytes.len()) };
-        bytes.copy_from_slice(flash_data);
-        Ok(())
-    }
-
-    pub fn blocking_write(&mut self, offset: u32, buf: &[u8]) -> Result<(), Error> {
-        let offset = FLASH_BASE as u32 + offset;
-        if offset as usize + buf.len() > FLASH_END {
-            return Err(Error::Size);
-        }
-        if offset as usize % WRITE_SIZE != 0 || buf.len() as usize % WRITE_SIZE != 0 {
-            return Err(Error::Unaligned);
-        }
-        trace!("Writing {} bytes at 0x{:x}", buf.len(), offset);
-
-        self.clear_all_err();
-
-        unsafe {
-            family::unlock();
-            let res = family::blocking_write(offset, buf);
-            family::lock();
-            res
-        }
-    }
+#[derive(Debug)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct FlashRegion {
+    pub bank: FlashBank,
+    pub base: u32,
+    pub size: u32,
+    pub erase_size: u32,
+    pub write_size: u32,
+    pub erase_value: u8,
+}
 
-    pub fn blocking_erase(&mut self, from: u32, to: u32) -> Result<(), Error> {
-        let from = FLASH_BASE as u32 + from;
-        let to = FLASH_BASE as u32 + to;
-        if to < from || to as usize > FLASH_END {
-            return Err(Error::Size);
-        }
-        if (from as usize % ERASE_SIZE) != 0 || (to as usize % ERASE_SIZE) != 0 {
-            return Err(Error::Unaligned);
-        }
+#[derive(Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub struct FlashSector {
+    pub bank: FlashBank,
+    pub index_in_bank: u8,
+    pub start: u32,
+    pub size: u32,
+}
 
-        self.clear_all_err();
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "defmt", derive(defmt::Format))]
+pub enum FlashBank {
+    Bank1 = 0,
+    Bank2 = 1,
+    Otp,
+}
 
-        unsafe {
-            family::unlock();
-            let res = family::blocking_erase(from, to);
-            family::lock();
-            res
-        }
+impl FlashRegion {
+    pub const fn end(&self) -> u32 {
+        self.base + self.size
     }
 
-    fn clear_all_err(&mut self) {
-        unsafe { family::clear_all_err() };
+    pub const fn sectors(&self) -> u8 {
+        (self.size / self.erase_size) as u8
     }
 }
 
-impl Drop for Flash<'_> {
-    fn drop(&mut self) {
-        unsafe { family::lock() };
-    }
-}
+#[cfg_attr(any(flash_l0, flash_l1, flash_l4, flash_wl, flash_wb), path = "l.rs")]
+#[cfg_attr(flash_f3, path = "f3.rs")]
+#[cfg_attr(flash_f4, path = "f4.rs")]
+#[cfg_attr(flash_f7, path = "f7.rs")]
+#[cfg_attr(flash_h7, path = "h7.rs")]
+#[cfg_attr(
+    not(any(
+        flash_l0, flash_l1, flash_l4, flash_wl, flash_wb, flash_f3, flash_f4, flash_f7, flash_h7
+    )),
+    path = "other.rs"
+)]
+mod family;
+
+#[allow(unused_imports)]
+pub use family::*;
 
 #[derive(Debug, Copy, Clone, PartialEq, Eq)]
 #[cfg_attr(feature = "defmt", derive(defmt::Format))]
@@ -97,10 +75,6 @@ pub enum Error {
     Parallelism,
 }
 
-impl<'d> ErrorType for Flash<'d> {
-    type Error = Error;
-}
-
 impl NorFlashError for Error {
     fn kind(&self) -> NorFlashErrorKind {
         match self {
@@ -110,28 +84,3 @@ impl NorFlashError for Error {
         }
     }
 }
-
-impl<'d> ReadNorFlash for Flash<'d> {
-    const READ_SIZE: usize = WRITE_SIZE;
-
-    fn read(&mut self, offset: u32, bytes: &mut [u8]) -> Result<(), Self::Error> {
-        self.blocking_read(offset, bytes)
-    }
-
-    fn capacity(&self) -> usize {
-        FLASH_SIZE
-    }
-}
-
-impl<'d> NorFlash for Flash<'d> {
-    const WRITE_SIZE: usize = WRITE_SIZE;
-    const ERASE_SIZE: usize = ERASE_SIZE;
-
-    fn erase(&mut self, from: u32, to: u32) -> Result<(), Self::Error> {
-        self.blocking_erase(from, to)
-    }
-
-    fn write(&mut self, offset: u32, bytes: &[u8]) -> Result<(), Self::Error> {
-        self.blocking_write(offset, bytes)
-    }
-}
diff --git a/embassy-stm32/src/flash/other.rs b/embassy-stm32/src/flash/other.rs
new file mode 100644
index 000000000..c151cb828
--- /dev/null
+++ b/embassy-stm32/src/flash/other.rs
@@ -0,0 +1,29 @@
+#![allow(unused)]
+
+use super::{Error, FlashRegion, FlashSector, FLASH_REGIONS, WRITE_SIZE};
+
+pub const fn get_flash_regions() -> &'static [&'static FlashRegion] {
+    &FLASH_REGIONS
+}
+
+pub(crate) unsafe fn lock() {
+    unimplemented!();
+}
+pub(crate) unsafe fn unlock() {
+    unimplemented!();
+}
+pub(crate) unsafe fn begin_write() {
+    unimplemented!();
+}
+pub(crate) unsafe fn end_write() {
+    unimplemented!();
+}
+pub(crate) unsafe fn blocking_write(_start_address: u32, _buf: &[u8; WRITE_SIZE]) -> Result<(), Error> {
+    unimplemented!();
+}
+pub(crate) unsafe fn blocking_erase_sector(_sector: &FlashSector) -> Result<(), Error> {
+    unimplemented!();
+}
+pub(crate) unsafe fn clear_all_err() {
+    unimplemented!();
+}
diff --git a/embassy-stm32/src/lib.rs b/embassy-stm32/src/lib.rs
index 8dc4df2dc..3f2d078f8 100644
--- a/embassy-stm32/src/lib.rs
+++ b/embassy-stm32/src/lib.rs
@@ -43,9 +43,6 @@ pub mod i2c;
 
 #[cfg(crc)]
 pub mod crc;
-#[cfg(any(
-    flash_l0, flash_l1, flash_wl, flash_wb, flash_l4, flash_f3, flash_f4, flash_f7, flash_h7
-))]
 pub mod flash;
 pub mod pwm;
 #[cfg(quadspi)]
diff --git a/examples/boot/bootloader/stm32/src/main.rs b/examples/boot/bootloader/stm32/src/main.rs
index b8027d19a..49c21920b 100644
--- a/examples/boot/bootloader/stm32/src/main.rs
+++ b/examples/boot/bootloader/stm32/src/main.rs
@@ -5,7 +5,7 @@ use cortex_m_rt::{entry, exception};
 #[cfg(feature = "defmt")]
 use defmt_rtt as _;
 use embassy_boot_stm32::*;
-use embassy_stm32::flash::{Flash, ERASE_SIZE};
+use embassy_stm32::flash::Flash;
 
 #[entry]
 fn main() -> ! {
@@ -19,9 +19,10 @@ fn main() -> ! {
         }
     */
 
-    let mut bl: BootLoader<ERASE_SIZE> = BootLoader::default();
+    let mut bl: BootLoader<2048> = BootLoader::default();
     let flash = Flash::new(p.FLASH);
-    let mut flash = BootFlash::new(flash);
+    let layout = flash.into_regions();
+    let mut flash = BootFlash::new(layout.bank1_region);
     let start = bl.prepare(&mut SingleFlashConfig::new(&mut flash));
     core::mem::drop(flash);
     unsafe { bl.load(start) }
diff --git a/examples/stm32f3/src/bin/flash.rs b/examples/stm32f3/src/bin/flash.rs
index baa7484d0..e40ad4fc0 100644
--- a/examples/stm32f3/src/bin/flash.rs
+++ b/examples/stm32f3/src/bin/flash.rs
@@ -15,7 +15,7 @@ async fn main(_spawner: Spawner) {
 
     const ADDR: u32 = 0x26000;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank1_region;
 
     info!("Reading...");
     let mut buf = [0u8; 8];
diff --git a/examples/stm32f4/src/bin/flash.rs b/examples/stm32f4/src/bin/flash.rs
index 7ea068a42..bd3a7c95e 100644
--- a/examples/stm32f4/src/bin/flash.rs
+++ b/examples/stm32f4/src/bin/flash.rs
@@ -5,7 +5,6 @@
 use defmt::{info, unwrap};
 use embassy_executor::Spawner;
 use embassy_stm32::flash::Flash;
-use embedded_storage::nor_flash::{NorFlash, ReadNorFlash};
 use {defmt_rtt as _, panic_probe as _};
 
 #[embassy_executor::main]
@@ -13,6 +12,8 @@ async fn main(_spawner: Spawner) {
     let p = embassy_stm32::init(Default::default());
     info!("Hello Flash!");
 
+    // Once can also call `into_regions()` to get access to NorFlash implementations
+    // for each of the unique characteristics.
     let mut f = Flash::new(p.FLASH);
 
     // Sector 5
@@ -30,19 +31,19 @@ fn test_flash(f: &mut Flash, offset: u32, size: u32) {
 
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(offset, &mut buf));
+    unwrap!(f.blocking_read(offset, &mut buf));
     info!("Read: {=[u8]:x}", buf);
 
     info!("Erasing...");
-    unwrap!(f.erase(offset, offset + size));
+    unwrap!(f.blocking_erase(offset, offset + size));
 
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(offset, &mut buf));
+    unwrap!(f.blocking_read(offset, &mut buf));
     info!("Read after erase: {=[u8]:x}", buf);
 
     info!("Writing...");
-    unwrap!(f.write(
+    unwrap!(f.blocking_write(
         offset,
         &[
             1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
@@ -52,7 +53,7 @@ fn test_flash(f: &mut Flash, offset: u32, size: u32) {
 
     info!("Reading...");
     let mut buf = [0u8; 32];
-    unwrap!(f.read(offset, &mut buf));
+    unwrap!(f.blocking_read(offset, &mut buf));
     info!("Read: {=[u8]:x}", buf);
     assert_eq!(
         &buf[..],
diff --git a/examples/stm32f7/src/bin/flash.rs b/examples/stm32f7/src/bin/flash.rs
index 4a7bca1fa..aabfe8557 100644
--- a/examples/stm32f7/src/bin/flash.rs
+++ b/examples/stm32f7/src/bin/flash.rs
@@ -14,12 +14,12 @@ async fn main(_spawner: Spawner) {
     let p = embassy_stm32::init(Default::default());
     info!("Hello Flash!");
 
-    const ADDR: u32 = 0x8_0000;
+    const ADDR: u32 = 0x8_0000; // This is the offset into the third region, the absolute address is 4x32K + 128K + 0x8_0000.
 
     // wait a bit before accessing the flash
     Timer::after(Duration::from_millis(300)).await;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank1_region3;
 
     info!("Reading...");
     let mut buf = [0u8; 32];
diff --git a/examples/stm32h7/src/bin/flash.rs b/examples/stm32h7/src/bin/flash.rs
index ee86bdbf6..7ee9838c9 100644
--- a/examples/stm32h7/src/bin/flash.rs
+++ b/examples/stm32h7/src/bin/flash.rs
@@ -14,12 +14,12 @@ async fn main(_spawner: Spawner) {
     let p = embassy_stm32::init(Default::default());
     info!("Hello Flash!");
 
-    const ADDR: u32 = 0x08_0000;
+    const ADDR: u32 = 0; // This is the offset into bank 2, the absolute address is 0x8_0000
 
     // wait a bit before accessing the flash
     Timer::after(Duration::from_millis(300)).await;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank2_region;
 
     info!("Reading...");
     let mut buf = [0u8; 32];
diff --git a/examples/stm32l0/src/bin/flash.rs b/examples/stm32l0/src/bin/flash.rs
index ffe4fb10b..337425028 100644
--- a/examples/stm32l0/src/bin/flash.rs
+++ b/examples/stm32l0/src/bin/flash.rs
@@ -15,7 +15,7 @@ async fn main(_spawner: Spawner) {
 
     const ADDR: u32 = 0x26000;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank1_region;
 
     info!("Reading...");
     let mut buf = [0u8; 8];
diff --git a/examples/stm32l1/src/bin/flash.rs b/examples/stm32l1/src/bin/flash.rs
index 476ed51a4..38feb0d76 100644
--- a/examples/stm32l1/src/bin/flash.rs
+++ b/examples/stm32l1/src/bin/flash.rs
@@ -15,7 +15,7 @@ async fn main(_spawner: Spawner) {
 
     const ADDR: u32 = 0x26000;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank1_region;
 
     info!("Reading...");
     let mut buf = [0u8; 8];
diff --git a/examples/stm32wl/src/bin/flash.rs b/examples/stm32wl/src/bin/flash.rs
index 2a8880624..e6bc2865c 100644
--- a/examples/stm32wl/src/bin/flash.rs
+++ b/examples/stm32wl/src/bin/flash.rs
@@ -15,7 +15,7 @@ async fn main(_spawner: Spawner) {
 
     const ADDR: u32 = 0x36000;
 
-    let mut f = Flash::new(p.FLASH);
+    let mut f = Flash::new(p.FLASH).into_regions().bank1_region;
 
     info!("Reading...");
     let mut buf = [0u8; 8];