diff --git a/libraries/AP_Filesystem/AP_Filesystem.h b/libraries/AP_Filesystem/AP_Filesystem.h
index b7f1938b93..c9106e0b1e 100644
--- a/libraries/AP_Filesystem/AP_Filesystem.h
+++ b/libraries/AP_Filesystem/AP_Filesystem.h
@@ -22,7 +22,7 @@
 #include <stdint.h>
 #include <AP_HAL/AP_HAL_Boards.h>
 
-#include "AP_Filesystem_Available.h"
+#include "AP_Filesystem_config.h"
 
 #ifndef MAX_NAME_LEN
 #define MAX_NAME_LEN 255
diff --git a/libraries/AP_Filesystem/AP_Filesystem_backend.h b/libraries/AP_Filesystem/AP_Filesystem_backend.h
index f359891cf9..178369e338 100644
--- a/libraries/AP_Filesystem/AP_Filesystem_backend.h
+++ b/libraries/AP_Filesystem/AP_Filesystem_backend.h
@@ -20,7 +20,7 @@
 #include <stdint.h>
 #include <AP_HAL/AP_HAL_Boards.h>
 
-#include "AP_Filesystem_Available.h"
+#include "AP_Filesystem_config.h"
 
 #include <AP_InternalError/AP_InternalError.h>
 
diff --git a/libraries/AP_Filesystem/AP_Filesystem_config.h b/libraries/AP_Filesystem/AP_Filesystem_config.h
index 52e26ef480..f0b0f8bdc9 100644
--- a/libraries/AP_Filesystem/AP_Filesystem_config.h
+++ b/libraries/AP_Filesystem/AP_Filesystem_config.h
@@ -4,6 +4,12 @@
 
 #include <AP_Mission/AP_Mission_config.h>
 
+#if HAL_OS_POSIX_IO || HAL_OS_FATFS_IO
+#define HAVE_FILESYSTEM_SUPPORT 1
+#else
+#define HAVE_FILESYSTEM_SUPPORT 0
+#endif
+
 #ifndef AP_FILESYSTEM_PARAM_ENABLED
 #define AP_FILESYSTEM_PARAM_ENABLED 1
 #endif