diff --git a/lib/efi_loader/efi_unicode_collation.c b/lib/efi_loader/efi_unicode_collation.c
index 4fe23625558..243c51a8dbe 100644
--- a/lib/efi_loader/efi_unicode_collation.c
+++ b/lib/efi_loader/efi_unicode_collation.c
@@ -11,8 +11,8 @@
 #include <cp437.h>
 #include <efi_loader.h>
 
-/* Characters that may not be used in file names */
-static const char illegal[] = "<>:\"/\\|?*\x7f";
+/* Characters that may not be used in FAT 8.3 file names */
+static const char illegal[] = "+,<=>:;\"/\\|?*[]\x7f";
 
 /*
  * EDK2 assumes codepage 1250 when creating FAT 8.3 file names.