diff --git a/src/modules/px4iofirmware/mixer.cpp b/src/modules/px4iofirmware/mixer.cpp
index 6a44294619..9558198f35 100644
--- a/src/modules/px4iofirmware/mixer.cpp
+++ b/src/modules/px4iofirmware/mixer.cpp
@@ -267,7 +267,7 @@ mixer_callback(uintptr_t handle,
 	       uint8_t control_index,
 	       float &control)
 {
-	if (control_group > 3)
+	if (control_group >= PX4IO_CONTROL_GROUPS)
 		return -1;
 
 	switch (source) {
diff --git a/src/modules/px4iofirmware/px4io.h b/src/modules/px4iofirmware/px4io.h
index bb224f3880..54c5663a5b 100644
--- a/src/modules/px4iofirmware/px4io.h
+++ b/src/modules/px4iofirmware/px4io.h
@@ -53,7 +53,7 @@
  */
 #define PX4IO_SERVO_COUNT		8
 #define PX4IO_CONTROL_CHANNELS		8
-#define PX4IO_CONTROL_GROUPS		2
+#define PX4IO_CONTROL_GROUPS		4
 #define PX4IO_RC_INPUT_CHANNELS		18
 #define PX4IO_RC_MAPPED_CONTROL_CHANNELS		8 /**< This is the maximum number of channels mapped/used */