diff --git a/sw/airborne/sim/i2c_hw.c b/sw/airborne/sim/i2c_hw.c
index 5bcbdf8987..37d9c6df38 100644
--- a/sw/airborne/sim/i2c_hw.c
+++ b/sw/airborne/sim/i2c_hw.c
@@ -2,4 +2,4 @@
 
 void i2c_hw_init ( void ) {}
 
-bool_t i2c_submit(struct i2c_periph* p, struct i2c_transaction* t) { return TRUE;}
+bool_t i2c_submit(struct i2c_periph* p __attribute__ ((unused)), struct i2c_transaction* t __attribute__ ((unused))) { return TRUE;}