diff --git a/src/modules/mavlink/mavlink_ftp.cpp b/src/modules/mavlink/mavlink_ftp.cpp
index a376392c00..058e9d95f1 100644
--- a/src/modules/mavlink/mavlink_ftp.cpp
+++ b/src/modules/mavlink/mavlink_ftp.cpp
@@ -1160,7 +1160,7 @@ bool MavlinkFTP::_validatePathIsWritable(const char *path)
 	// Don't allow writes to system paths as they are in RAM
 	// Ideally we'd canonicalize the path (with 'realpath'), but it might not exist, so realpath() would fail.
 	// The next simpler thing is to check there's no reference to a parent dir.
-	if (strncmp(path, "/fs/microsd/", 12) != 0 || strstr(path, "/../") != nullptr) {
+	if (strncmp(path, CONFIG_BOARD_ROOT_PATH "/", 12) != 0 || strstr(path, "/../") != nullptr) {
 		PX4_ERR("Disallowing write to %s", path);
 		return false;
 	}
diff --git a/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp
index 288023a650..2accd21c54 100644
--- a/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp
+++ b/src/modules/mavlink/mavlink_tests/mavlink_ftp_test.cpp
@@ -43,7 +43,7 @@
 #include "../mavlink_ftp.h"
 
 #ifdef __PX4_NUTTX
-#define PX4_MAVLINK_TEST_DATA_DIR "/fs/microsd/ftp_unit_test_data"
+#define PX4_MAVLINK_TEST_DATA_DIR CONFIG_BOARD_ROOT_PATH "/ftp_unit_test_data"
 #else
 #define PX4_MAVLINK_TEST_DATA_DIR "ftp_unit_test_data"
 #endif