diff --git a/VKernel/Kernel/drivers/fs/fat32/fat32_types.vp b/VKernel/Kernel/drivers/fs/fat32/fat32_types.vp
index 71eac35..b55e399 100644
--- a/VKernel/Kernel/drivers/fs/fat32/fat32_types.vp
+++ b/VKernel/Kernel/drivers/fs/fat32/fat32_types.vp
@@ -719,6 +719,12 @@ class volinfo:
 	def dir_find(self, dp: dirobj | t.CPtr, name: t.CConst | t.CChar | t.CPtr, lfn_buf: t.CUInt16T | t.CPtr) -> FRESULT:
 		sfn: t.CArray[t.CChar, 12]
 		sfn_from_lfn(name, c.Addr(sfn[0]))
+		# [DIAG] sfn 生成字节 hex（hello.elf 应 HELLO..ELF，异常时显示 sfn=H）
+		_dbhs: t.CArray[t.CChar, 64]
+		viperlib.snprintf(c.Addr(_dbhs), 64, "[sfn] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x\n",
+			sfn[0], sfn[1], sfn[2], sfn[3], sfn[4], sfn[5],
+			sfn[6], sfn[7], sfn[8], sfn[9], sfn[10])
+		serial.puts(c.Addr(_dbhs))
 		_dbg_sfn: t.CArray[t.CChar, 16]
 		_si: t.CInt
 		for _si in range(11):