diff --git a/libraries/AP_HAL_ChibiOS/hwdef/common/ffconf.h b/libraries/AP_HAL_ChibiOS/hwdef/common/ffconf.h
index c3d2b53f2c..ff12e35eec 100644
--- a/libraries/AP_HAL_ChibiOS/hwdef/common/ffconf.h
+++ b/libraries/AP_HAL_ChibiOS/hwdef/common/ffconf.h
@@ -246,7 +246,7 @@
 /      lock control is independent of re-entrancy. */
 
 
-#define _FS_REENTRANT   0
+#define _FS_REENTRANT   1
 #define _FS_TIMEOUT     MS2ST(1000)
 #define _SYNC_t         semaphore_t*
 /* The option _FS_REENTRANT switches the re-entrancy (thread safe) of the FatFs