diff --git a/libraries/AP_HAL_PX4/RCOutput.cpp b/libraries/AP_HAL_PX4/RCOutput.cpp
index 507bc546d8..4ada16dcb4 100644
--- a/libraries/AP_HAL_PX4/RCOutput.cpp
+++ b/libraries/AP_HAL_PX4/RCOutput.cpp
@@ -55,10 +55,14 @@ void PX4RCOutput::init()
     }
 
 #if !defined(CONFIG_ARCH_BOARD_PX4FMU_V4)
-    _alt_fd = open("/dev/px4fmu", O_RDWR);
-    if (_alt_fd == -1) {
-        hal.console->printf("RCOutput: failed to open /dev/px4fmu");
-        return;
+    struct stat st;
+    // don't try and open px4fmu unless there is a px4io. Otherwise we
+    // can end up opening the same device twice
+    if (stat("/dev/px4io", &st) == 0) {
+        _alt_fd = open("/dev/px4fmu", O_RDWR);
+        if (_alt_fd == -1) {
+            hal.console->printf("RCOutput: failed to open /dev/px4fmu");
+        }
     }
 #endif