diff --git a/tools/firmware-utils/src/mkfwimage2.c b/tools/firmware-utils/src/mkfwimage2.c
index ee09abba1..993c3d44e 100644
--- a/tools/firmware-utils/src/mkfwimage2.c
+++ b/tools/firmware-utils/src/mkfwimage2.c
@@ -212,7 +212,7 @@ static int image_layout_add_partition(const char *part_desc)
 	}
 
 	d = &im.parts[im.part_count];
-	t = sscanf(part_desc, "%15[a-zA-Z]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%256s",
+	t = sscanf(part_desc, "%15[0-9a-zA-Z]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%15[0-9a-fA-Fx]:%256s",
 			d->partition_name,
 			offset,
 			length,