diff --git a/embassy-stm32/src/dac/mod.rs b/embassy-stm32/src/dac/mod.rs
index 46c485b3..0a15563e 100644
--- a/embassy-stm32/src/dac/mod.rs
+++ b/embassy-stm32/src/dac/mod.rs
@@ -7,8 +7,7 @@ use crate::peripherals;
 pub use _version::*;
 
 pub(crate) mod sealed {
-    use super::*;
-    use crate::gpio::{OptionalPin, Pin};
+    use crate::gpio::OptionalPin;
 
     pub trait Instance {
         fn regs() -> &'static crate::pac::dac::Dac;
diff --git a/embassy-stm32/src/dac/v2.rs b/embassy-stm32/src/dac/v2.rs
index 18ac0f86..a7aad04f 100644
--- a/embassy-stm32/src/dac/v2.rs
+++ b/embassy-stm32/src/dac/v2.rs
@@ -1,11 +1,12 @@
 use crate::dac::{DacPin, Instance};
-use crate::gpio::Pin;
-use crate::gpio::{AnyPin, OptionalPin};
+use crate::fmt::*;
+use crate::gpio::AnyPin;
 use crate::pac::dac;
 use core::marker::PhantomData;
 use embassy::util::Unborrow;
 use embassy_extras::unborrow;
 
+#[derive(Debug, defmt::Format)]
 pub enum Error {
     UnconfiguredChannel,
     InvalidValue,
@@ -77,7 +78,6 @@ pub enum Value {
 }
 
 pub struct Dac<'d, T: Instance> {
-    //peri: T,
     ch1: Option<AnyPin>,
     ch2: Option<AnyPin>,
     phantom: PhantomData<&'d mut T>,
@@ -85,11 +85,10 @@ pub struct Dac<'d, T: Instance> {
 
 impl<'d, T: Instance> Dac<'d, T> {
     pub fn new(
-        peri: impl Unborrow<Target = T> + 'd,
+        _peri: impl Unborrow<Target = T> + 'd,
         ch1: impl Unborrow<Target = impl DacPin<T, 1>>,
         ch2: impl Unborrow<Target = impl DacPin<T, 2>>,
     ) -> Self {
-        unborrow!(peri);
         unborrow!(ch1, ch2);
 
         let ch1 = ch1.degrade_optional();
@@ -110,13 +109,11 @@ impl<'d, T: Instance> Dac<'d, T> {
             }
         }
 
-        let mut dac = Self {
+        Self {
             ch1,
             ch2,
             phantom: PhantomData,
-        };
-
-        dac
+        }
     }
 
     pub fn enable_channel(&mut self, ch: Channel) -> Result<(), Error> {
@@ -181,7 +178,7 @@ impl<'d, T: Instance> Dac<'d, T> {
         if self.ch1.is_none() {
             return Err(Error::UnconfiguredChannel);
         }
-        self.disable_channel(Channel::Ch1);
+        unwrap!(self.disable_channel(Channel::Ch1));
         unsafe {
             T::regs().cr().modify(|reg| {
                 reg.set_tsel1(trigger.tsel());
@@ -194,7 +191,7 @@ impl<'d, T: Instance> Dac<'d, T> {
         if self.ch2.is_none() {
             return Err(Error::UnconfiguredChannel);
         }
-        self.disable_channel(Channel::Ch2);
+        unwrap!(self.disable_channel(Channel::Ch2));
         unsafe {
             T::regs().cr().modify(|reg| {
                 reg.set_tsel2(trigger.tsel());
diff --git a/embassy-stm32/src/dma/v2.rs b/embassy-stm32/src/dma/v2.rs
index ba13f8d4..5b250546 100644
--- a/embassy-stm32/src/dma/v2.rs
+++ b/embassy-stm32/src/dma/v2.rs
@@ -35,6 +35,7 @@ impl State {
 
 static STATE: State = State::new();
 
+#[allow(unused)] // Used by usart/v1.rs which may or may not be enabled
 pub(crate) async unsafe fn transfer_m2p(
     ch: &mut impl Channel,
     ch_func: u8,
diff --git a/embassy-stm32/src/i2c/mod.rs b/embassy-stm32/src/i2c/mod.rs
index 0f9414c5..c108a0a8 100644
--- a/embassy-stm32/src/i2c/mod.rs
+++ b/embassy-stm32/src/i2c/mod.rs
@@ -16,7 +16,6 @@ pub enum Error {
 }
 
 pub(crate) mod sealed {
-    use super::*;
     use crate::gpio::Pin;
 
     pub trait Instance {
diff --git a/embassy-stm32/src/i2c/v1.rs b/embassy-stm32/src/i2c/v1.rs
index ac971963..91bc37db 100644
--- a/embassy-stm32/src/i2c/v1.rs
+++ b/embassy-stm32/src/i2c/v1.rs
@@ -1,5 +1,3 @@
-use crate::gpio::AnyPin;
-use crate::gpio::Pin;
 use crate::i2c::{Error, Instance, SclPin, SdaPin};
 use crate::time::Hertz;
 use core::marker::PhantomData;
@@ -10,24 +8,18 @@ use embedded_hal::blocking::i2c::Write;
 use embedded_hal::blocking::i2c::WriteRead;
 
 use crate::pac::i2c;
-use crate::pac::i2c::I2c as I2cTrait;
-use core::cmp;
 
 use crate::pac::gpio::vals::{Afr, Moder, Ot};
 use crate::pac::gpio::Gpio;
-use core::ops::Deref;
 
 pub struct I2c<'d, T: Instance> {
-    //peri: T,
-    scl: AnyPin,
-    sda: AnyPin,
     phantom: PhantomData<&'d mut T>,
 }
 
 impl<'d, T: Instance> I2c<'d, T> {
     pub fn new<F>(
         pclk: Hertz,
-        peri: impl Unborrow<Target = T> + 'd,
+        _peri: impl Unborrow<Target = T> + 'd,
         scl: impl Unborrow<Target = impl SclPin<T>>,
         sda: impl Unborrow<Target = impl SdaPin<T>>,
         freq: F,
@@ -35,7 +27,6 @@ impl<'d, T: Instance> I2c<'d, T> {
     where
         F: Into<Hertz>,
     {
-        unborrow!(peri);
         unborrow!(scl, sda);
 
         unsafe {
@@ -66,9 +57,6 @@ impl<'d, T: Instance> I2c<'d, T> {
             });
         }
 
-        let scl = scl.degrade();
-        let sda = sda.degrade();
-
         unsafe {
             T::regs().cr1().modify(|reg| {
                 reg.set_pe(true);
@@ -76,8 +64,6 @@ impl<'d, T: Instance> I2c<'d, T> {
         }
 
         Self {
-            scl,
-            sda,
             phantom: PhantomData,
         }
     }
@@ -261,7 +247,7 @@ impl<'d, T: Instance> Read for I2c<'d, T> {
             *last = unsafe { self.recv_byte()? };
 
             // Wait for the STOP to be sent.
-            while { unsafe { T::regs().cr1().read().stop() == i2c::vals::Stop::STOP } } {}
+            while unsafe { T::regs().cr1().read().stop() == i2c::vals::Stop::STOP } {}
 
             // Fallthrough is success
             Ok(())
@@ -282,7 +268,7 @@ impl<'d, T: Instance> Write for I2c<'d, T> {
                 .cr1()
                 .modify(|reg| reg.set_stop(i2c::vals::Stop::STOP));
             // Wait for STOP condition to transmit.
-            while { unsafe { T::regs().cr1().read().stop() == i2c::vals::Stop::STOP } } {}
+            while T::regs().cr1().read().stop() == i2c::vals::Stop::STOP {}
         };
 
         // Fallthrough is success
diff --git a/embassy-stm32/src/i2c/v2.rs b/embassy-stm32/src/i2c/v2.rs
index 80d8fc0c..03ad29f1 100644
--- a/embassy-stm32/src/i2c/v2.rs
+++ b/embassy-stm32/src/i2c/v2.rs
@@ -6,26 +6,20 @@ use embedded_hal::blocking::i2c::Read;
 use embedded_hal::blocking::i2c::Write;
 use embedded_hal::blocking::i2c::WriteRead;
 
-use crate::gpio::AnyPin;
-use crate::gpio::Pin;
 use crate::i2c::{Error, Instance, SclPin, SdaPin};
 use crate::pac::gpio::vals::{Afr, Moder, Ot};
 use crate::pac::gpio::Gpio;
 use crate::pac::i2c;
-use crate::pac::i2c::I2c as I2cTrait;
 use crate::time::Hertz;
 
 pub struct I2c<'d, T: Instance> {
-    //peri: T,
-    scl: AnyPin,
-    sda: AnyPin,
     phantom: PhantomData<&'d mut T>,
 }
 
 impl<'d, T: Instance> I2c<'d, T> {
     pub fn new<F>(
         pclk: Hertz,
-        peri: impl Unborrow<Target = T> + 'd,
+        _peri: impl Unborrow<Target = T> + 'd,
         scl: impl Unborrow<Target = impl SclPin<T>>,
         sda: impl Unborrow<Target = impl SdaPin<T>>,
         freq: F,
@@ -33,7 +27,6 @@ impl<'d, T: Instance> I2c<'d, T> {
     where
         F: Into<Hertz>,
     {
-        unborrow!(peri);
         unborrow!(scl, sda);
 
         unsafe {
@@ -60,9 +53,6 @@ impl<'d, T: Instance> I2c<'d, T> {
             });
         }
 
-        let scl = scl.degrade();
-        let sda = sda.degrade();
-
         unsafe {
             T::regs().cr1().modify(|reg| {
                 reg.set_pe(true);
@@ -70,8 +60,6 @@ impl<'d, T: Instance> I2c<'d, T> {
         }
 
         Self {
-            scl,
-            sda,
             phantom: PhantomData,
         }
     }
@@ -110,7 +98,7 @@ impl<'d, T: Instance> I2c<'d, T> {
                 w.set_rd_wrn(i2c::vals::RdWrn::READ);
                 w.set_nbytes(length as u8);
                 w.set_start(i2c::vals::Start::START);
-                w.set_autoend(i2c::vals::Autoend::AUTOMATIC);
+                w.set_autoend(stop.autoend());
             });
         }
     }
diff --git a/embassy-stm32/src/spi/v2.rs b/embassy-stm32/src/spi/v2.rs
index 1c10ab1b..46fe817e 100644
--- a/embassy-stm32/src/spi/v2.rs
+++ b/embassy-stm32/src/spi/v2.rs
@@ -29,7 +29,6 @@ impl WordSize {
 }
 
 pub struct Spi<'d, T: Instance> {
-    //peri: T,
     sck: AnyPin,
     mosi: AnyPin,
     miso: AnyPin,
@@ -39,7 +38,7 @@ pub struct Spi<'d, T: Instance> {
 impl<'d, T: Instance> Spi<'d, T> {
     pub fn new<F>(
         pclk: Hertz,
-        peri: impl Unborrow<Target = T> + 'd,
+        _peri: impl Unborrow<Target = T> + 'd,
         sck: impl Unborrow<Target = impl SckPin<T>>,
         mosi: impl Unborrow<Target = impl MosiPin<T>>,
         miso: impl Unborrow<Target = impl MisoPin<T>>,
@@ -49,7 +48,6 @@ impl<'d, T: Instance> Spi<'d, T> {
     where
         F: Into<Hertz>,
     {
-        unborrow!(peri);
         unborrow!(sck, mosi, miso);
 
         unsafe {
@@ -95,7 +93,6 @@ impl<'d, T: Instance> Spi<'d, T> {
         }
 
         Self {
-            //peri,
             sck,
             mosi,
             miso,
diff --git a/embassy-stm32/src/spi/v3.rs b/embassy-stm32/src/spi/v3.rs
index c3f66430..da4686b9 100644
--- a/embassy-stm32/src/spi/v3.rs
+++ b/embassy-stm32/src/spi/v3.rs
@@ -20,7 +20,7 @@ impl WordSize {
         }
     }
 
-    fn frxth(&self) -> spi::vals::Fthlv {
+    fn _frxth(&self) -> spi::vals::Fthlv {
         match self {
             WordSize::EightBit => spi::vals::Fthlv::ONEFRAME,
             WordSize::SixteenBit => spi::vals::Fthlv::ONEFRAME,
@@ -29,7 +29,6 @@ impl WordSize {
 }
 
 pub struct Spi<'d, T: Instance> {
-    //peri: T,
     sck: AnyPin,
     mosi: AnyPin,
     miso: AnyPin,
@@ -39,7 +38,7 @@ pub struct Spi<'d, T: Instance> {
 impl<'d, T: Instance> Spi<'d, T> {
     pub fn new<F>(
         pclk: Hertz,
-        peri: impl Unborrow<Target = T> + 'd,
+        _peri: impl Unborrow<Target = T> + 'd,
         sck: impl Unborrow<Target = impl SckPin<T>>,
         mosi: impl Unborrow<Target = impl MosiPin<T>>,
         miso: impl Unborrow<Target = impl MisoPin<T>>,
@@ -49,7 +48,6 @@ impl<'d, T: Instance> Spi<'d, T> {
     where
         F: Into<Hertz>,
     {
-        unborrow!(peri);
         unborrow!(sck, mosi, miso);
 
         unsafe {
@@ -110,7 +108,6 @@ impl<'d, T: Instance> Spi<'d, T> {
         }
 
         Self {
-            //peri,
             sck,
             mosi,
             miso,
@@ -218,7 +215,7 @@ impl<'d, T: Instance> embedded_hal::blocking::spi::Transfer<u8> for Spi<'d, T> {
         Self::set_word_size(WordSize::EightBit);
         let regs = T::regs();
 
-        for (i, word) in words.iter_mut().enumerate() {
+        for word in words.iter_mut() {
             unsafe {
                 regs.cr1().modify(|reg| {
                     reg.set_ssi(false);
diff --git a/examples/stm32f4/Cargo.toml b/examples/stm32f4/Cargo.toml
index 2c16af5f..8625f83b 100644
--- a/examples/stm32f4/Cargo.toml
+++ b/examples/stm32f4/Cargo.toml
@@ -28,8 +28,8 @@ defmt-rtt = "0.2.0"
 
 cortex-m = "0.7.1"
 cortex-m-rt = "0.6.14"
-embedded-hal    = { version = "0.2.4" }
+embedded-hal = { version = "0.2.4" }
 panic-probe = { version = "0.2.0", features= ["print-defmt"] }
 futures = { version = "0.3.8", default-features = false, features = ["async-await"] }
 rtt-target = { version = "0.3", features = ["cortex-m"] }
-heapless            = { version = "0.7.1", default-features = false }
\ No newline at end of file
+heapless = { version = "0.7.1", default-features = false }