diff --git a/libcortex_a9/src/mutex.rs b/libcortex_a9/src/mutex.rs
index b8eda33..de0d705 100644
--- a/libcortex_a9/src/mutex.rs
+++ b/libcortex_a9/src/mutex.rs
@@ -32,7 +32,7 @@ impl<T> Mutex<T> {
     /// Lock the Mutex, blocks when already locked
     pub fn lock(&self) -> MutexGuard<T> {
         let mut irq = unsafe { enter_critical() };
-        while self.locked.compare_and_swap(UNLOCKED, LOCKED, Ordering::AcqRel) != UNLOCKED {
+        while self.locked.compare_exchange_weak(UNLOCKED, LOCKED, Ordering::AcqRel, Ordering::Relaxed).is_err() {
             unsafe {
                 exit_critical(irq);
                 spin_lock_yield();
@@ -44,7 +44,7 @@ impl<T> Mutex<T> {
 
     pub fn try_lock(&self) -> Option<MutexGuard<T>> {
         let irq = unsafe { enter_critical() };
-        if self.locked.compare_and_swap(UNLOCKED, LOCKED, Ordering::AcqRel) != UNLOCKED {
+        if self.locked.compare_exchange_weak(UNLOCKED, LOCKED, Ordering::AcqRel, Ordering::Relaxed).is_err() {
             unsafe { exit_critical(irq) };
             None
         } else {
diff --git a/libcortex_a9/src/semaphore.rs b/libcortex_a9/src/semaphore.rs
index a188499..36243e9 100644
--- a/libcortex_a9/src/semaphore.rs
+++ b/libcortex_a9/src/semaphore.rs
@@ -20,7 +20,7 @@ impl Semaphore {
         loop {
             let value = self.value.load(Ordering::Relaxed);
             if value > 0 {
-                if self.value.compare_and_swap(value, value - 1, Ordering::SeqCst) == value {
+                if self.value.compare_exchange_weak(value, value - 1, Ordering::SeqCst, Ordering::Relaxed).is_ok() {
                     return Some(());
                 }
             } else {
@@ -58,7 +58,7 @@ impl Semaphore {
         loop {
             let value = self.value.load(Ordering::Relaxed);
             if value < self.max {
-                if self.value.compare_and_swap(value, value + 1, Ordering::SeqCst) == value {
+                if self.value.compare_exchange_weak(value, value + 1, Ordering::SeqCst, Ordering::Relaxed).is_ok() {
                     notify_spin_lock();
                     return;
                 }
diff --git a/libcortex_a9/src/uncached.rs b/libcortex_a9/src/uncached.rs
index 8712e27..1ff962c 100644
--- a/libcortex_a9/src/uncached.rs
+++ b/libcortex_a9/src/uncached.rs
@@ -2,7 +2,7 @@ use core::{
     ops::{Deref, DerefMut},
     mem::{align_of, size_of},
 };
-use alloc::alloc::{dealloc, Layout, LayoutErr};
+use alloc::alloc::{dealloc, Layout, LayoutError};
 use crate::mmu::{L1_PAGE_SIZE, L1Table};
 
 pub struct UncachedSlice<T: 'static> {
@@ -12,7 +12,7 @@ pub struct UncachedSlice<T: 'static> {
 
 impl<T> UncachedSlice<T> {
     /// allocates in chunks of 1 MB
-    pub fn new<F: Fn() -> T>(len: usize, default: F) -> Result<Self, LayoutErr> {
+    pub fn new<F: Fn() -> T>(len: usize, default: F) -> Result<Self, LayoutError> {
         // round to full pages
         let size = ((len * size_of::<T>() - 1) | (L1_PAGE_SIZE - 1)) + 1;
         let align = align_of::<T>()