diff --git a/Android.mk b/Android.mk
index fbb7184..78f24b5 100644
--- a/Android.mk
+++ b/Android.mk
@@ -48,7 +48,7 @@ ifdef BOARD_SDEXT_DEVICE
 endif
 
 ifdef BOARD_SDEXT_FILESYSTEM
-  LOCAL_CFLAGS += -DSDCARD_DEVICE_PRIMARY=\"$(BOARD_SDEXT_FILESYSTEM)\"
+  LOCAL_CFLAGS += -DSDEXT_FILESYSTEM=\"$(BOARD_SDEXT_FILESYSTEM)\"
 endif
 
 ifdef BOARD_DATA_DEVICE