diff --git a/dodo.py b/dodo.py
index f59ee5d..e6ded1c 100644
--- a/dodo.py
+++ b/dodo.py
@@ -88,6 +88,16 @@ def task_install_dep():
         ],
     }
 
+def task_check():
+    """ Run a compiler check on the code.
+    """
+    task = {
+        'file_dep': get_build_dep(),
+        'actions': [f'RUSTFLAGS="{consts.RUSTC_FLAGS}" cargo check --target={consts.TARGET} {consts.CARGO_COMPILE_FLAGS}'],
+    }
+    print(task)
+    return task
+
 def task_compile():
     """ Compile the sources.
     """
diff --git a/flash.sh b/flash.sh
new file mode 100755
index 0000000..8e450b8
--- /dev/null
+++ b/flash.sh
@@ -0,0 +1,5 @@
+#!/usr/bin/sh
+
+udisksctl mount -b /dev/disk/by-label/BOOT
+cp kernel8.img /run/media/me/BOOT/kernel8.img
+udisksctl unmount -b /dev/disk/by-label/BOOT
diff --git a/src/bsp/rpi3/uart.rs b/src/bsp/rpi3/uart.rs
index c6ff694..caf892b 100644
--- a/src/bsp/rpi3/uart.rs
+++ b/src/bsp/rpi3/uart.rs
@@ -4,24 +4,27 @@ use core::arch::asm;
 use core::fmt;
 
 use crate::traits::console::{Write, Console};
+use crate::traits::synchronization::{DummyMutex, Mutex};
 
 use super::memory_map::uart as mm;
 
-
 pub struct Uart<'a> {
+    inner: DummyMutex<UartInner<'a>>,
+}
+
+pub struct UartInner<'a> {
     initialized: bool,
     memory_map: &'a mm::UartMemoryMap,
 }
 
-impl<'a> Uart<'a> {
-    // TODO: not sure this should be public outside of bsp.
+impl<'a> UartInner<'a> {
     /// Constructor for [`Uart`].
-    pub const fn new(memory_map: &'a mm::UartMemoryMap) -> Self {
-        Uart { initialized: false, memory_map }
+    const fn new(memory_map: &'a mm::UartMemoryMap) -> Self {
+        Self { initialized: false, memory_map }
     }
 
     /// Initialise the UART.
-    pub fn init(&mut self) {
+    fn init(&mut self) {
         // TODO: Recover from possible previous test.
         
         self.flush();
@@ -68,55 +71,80 @@ impl<'a> Uart<'a> {
     fn is_tx_full(&self) -> bool {
         self.memory_map.fr_txff.read() != 0
     }
+
+    /// Write a character to the Uart
+    fn write_char(&self, c: char) {
+        if !self.initialized {
+            panic!("Cannot write to a non initialized UART");
+        }
+        while self.is_tx_full() {
+            use super::gpio;
+            let _ = gpio::set_pin_output_state(20, gpio::PinOutputState::High);
+            unsafe { asm!("nop") };
+        }
+        self.memory_map.dr_data.write_without_read(c as u32);
+    }
+
+    /// Flush the uart
+    fn flush(&self) {
+        while self.is_busy() {
+            unsafe { asm!("nop") };
+        }
+    }
 }
 
 // Allow the use of uart for fmt::Write::write_fmt.
-impl fmt::Write for Uart<'_> {
+impl fmt::Write for UartInner<'_> {
     fn write_str(&mut self, s: &str) -> fmt::Result {
         for c in s.chars() {
             if c == '\n' {
-                Write::write_char(self, '\r');
+                UartInner::write_char(self, '\r');
             }
-            Write::write_char(self, c);
+            UartInner::write_char(self, c);
         }
         Ok(())
     }
 }
 
-// TODO: add sync
 impl Write for Uart<'_> {
     fn write_char(&self, c: char) {
-        if !self.initialized {
-            //panic!("Cannot write to a non initialized UART");
-        }
-        while self.is_tx_full() {
-            use super::gpio;
-            let _ = gpio::set_pin_output_state(20, gpio::PinOutputState::High);
-            unsafe { asm!("nop") };
-        }
-        self.memory_map.dr_data.write_without_read(c as u32);
+        self.inner.lock(|uart| uart.write_char(c))
     }
 
     fn write_fmt(&self, args: fmt::Arguments) -> fmt::Result {
-        // TODO: use syncronisation here
-        let mut new_uart = Uart { initialized: self.initialized, memory_map: self.memory_map};
-        fmt::Write::write_fmt(&mut new_uart, args)
+        self.inner.lock(|uart| fmt::Write::write_fmt(uart, args))
     }
 
     fn flush(&self) {
-        while self.is_busy() {
-            unsafe { asm!("nop") };
+        self.inner.lock(|uart| uart.flush())
+    }
+}
+
+impl<'a> Uart<'a> {
+
+    // TODO: not sure this should be public? public in bsp only?
+    /// Create a new UART object
+    const fn new(memory_map: &'a mm::UartMemoryMap) -> Self {
+        Self {
+            inner: DummyMutex::new(
+                UartInner::new(memory_map)
+            )
         }
     }
+
+    /// Initialize the UART.
+    fn init(&self) {
+        self.inner.lock(|uart| uart.init())
+    }
 }
 
 impl Console for Uart<'_> {}
 
-static UART: Uart = Uart { initialized: true, memory_map: &mm::UART }; // TODO: use sync
+/// The UART object
+static UART: Uart = Uart::new(&mm::UART);
 
 pub fn init() {
-    let mut uart = Uart::new(&mm::UART);
-    uart.init();
+    UART.init();
 }
 
 // TODO: move?