diff --git a/extmod/vfs.h b/extmod/vfs.h
index 15bd2a5f5..004b002f5 100644
--- a/extmod/vfs.h
+++ b/extmod/vfs.h
@@ -50,6 +50,7 @@
 #define MP_BLOCKDEV_IOCTL_SYNC          (3)
 #define MP_BLOCKDEV_IOCTL_BLOCK_COUNT   (4)
 #define MP_BLOCKDEV_IOCTL_BLOCK_SIZE    (5)
+#define MP_BLOCKDEV_IOCTL_BLOCK_ERASE   (6)
 
 // At the moment the VFS protocol just has import_stat, but could be extended to other methods
 typedef struct _mp_vfs_proto_t {
diff --git a/extmod/vfs_lfsx.c b/extmod/vfs_lfsx.c
index 6aa82b1ef..e5826803b 100644
--- a/extmod/vfs_lfsx.c
+++ b/extmod/vfs_lfsx.c
@@ -52,7 +52,7 @@ STATIC int MP_VFS_LFSx(dev_prog)(const struct LFSx_API(config) *c, LFSx_API(bloc
 }
 
 STATIC int MP_VFS_LFSx(dev_erase)(const struct LFSx_API(config) *c, LFSx_API(block_t) block) {
-    return MP_VFS_LFSx(dev_ioctl)(c, 6, block, true); // erase
+    return MP_VFS_LFSx(dev_ioctl)(c, MP_BLOCKDEV_IOCTL_BLOCK_ERASE, block, true);
 }
 
 STATIC int MP_VFS_LFSx(dev_sync)(const struct LFSx_API(config) *c) {