diff --git a/extendedcommands.c b/extendedcommands.c
index bafa552..6799b2d 100644
--- a/extendedcommands.c
+++ b/extendedcommands.c
@@ -423,7 +423,7 @@
     LOGI("Formatting unknown device.\n");
 
     // device may simply be a name, like "system"
-    if (device[0] != '/')
+    if (get_flash_type(fs_type) != UNSUPPORTED)
         return erase_raw_partition(fs_type, device);
 
     // if this is SDEXT:, don't worry about it if it does not exist.