diff --git a/src/dos_m65/dev_sdcard/fs_hvsr_util_nextdirentry.s b/src/dos_m65/dev_sdcard/fs_hvsr_util_nextdirentry.s
index b2b1eb1e..c4e32f96 100644
--- a/src/dos_m65/dev_sdcard/fs_hvsr_util_nextdirentry.s
+++ b/src/dos_m65/dev_sdcard/fs_hvsr_util_nextdirentry.s
@@ -48,7 +48,7 @@ fs_hvsr_util_nextdirentry:
 
 	ldx FS_HVSR_DIRENT+$40             ; file name length
 	beq fs_hvsr_util_nextdirentry      ; do not even try for empty file name
-	cmp #20
+	cpx #20
 	bcs fs_hvsr_util_nextdirentry      ; if longer than 16 characters + dot + extension - also skip this one
 	dex