diff --git a/sw/airborne/avr/uart_hw.h b/sw/airborne/avr/uart_hw.h
index bb826b8799..0e892d80e9 100644
--- a/sw/airborne/avr/uart_hw.h
+++ b/sw/airborne/avr/uart_hw.h
@@ -31,6 +31,7 @@
 #define UART_HW_H
 
 #include <avr/io.h>
+#include <avr/signal.h>
 #include <avr/interrupt.h>
 #include "std.h"
 
diff --git a/sw/airborne/maxstream.c b/sw/airborne/maxstream.c
index 3a69c4c445..9696e69559 100644
--- a/sw/airborne/maxstream.c
+++ b/sw/airborne/maxstream.c
@@ -30,6 +30,7 @@
 #include "maxstream.h"
 #include "messages.h"
 #include "datalink.h"
+#include "uart.h"
 
 static uint8_t msg_lengths[] = MSG_LENGTHS;