diff --git a/conf/autopilot/twin_avr.makefile b/conf/autopilot/twin_avr.makefile
index de8fffdd4d..def93d33d4 100644
--- a/conf/autopilot/twin_avr.makefile
+++ b/conf/autopilot/twin_avr.makefile
@@ -24,3 +24,4 @@ tunnel.ARCHDIR = $(ARCHI)
 tunnel.ARCH = atmega128
 tunnel.TARGET = autopilot
 tunnel.TARGETDIR = autopilot
+tunnel.srcs += $(SRC_ARCH)/uart_tunnel.c
diff --git a/sw/airborne/avr/uart_tunnel.c b/sw/airborne/avr/uart_tunnel.c
index 0861ab0c37..475cb0a204 100644
--- a/sw/airborne/avr/uart_tunnel.c
+++ b/sw/airborne/avr/uart_tunnel.c
@@ -1,9 +1,9 @@
 #include <inttypes.h>
 #include <avr/io.h>
+#if (__GNUC__ == 3)
 #include <avr/signal.h>
+#endif
 #include <avr/interrupt.h>
-#include <math.h>
-
 
 #define UART_PC_PORT    PORTE
 #define UART_PC_DDR     DDRE