diff --git a/bootloader.c b/bootloader.c
index f4ac26b..1faf09d 100644
--- a/bootloader.c
+++ b/bootloader.c
@@ -20,7 +20,7 @@
 /** symbol for beginning of the application
  *  @note this symbol will be provided by the bootloader linker script
  */
-extern char __application_beginning;
+extern uint32_t __application_beginning;
 
 /** bootloader entry point */
 void main(void);