diff --git a/core/imgread/gdi.cpp b/core/imgread/gdi.cpp
index 5eaf87859..e1f650e93 100644
--- a/core/imgread/gdi.cpp
+++ b/core/imgread/gdi.cpp
@@ -36,9 +36,9 @@ Disc* load_gdi(const char* file)
 	strncpy(path, file, sizeof(path));
 	path[sizeof(path) - 1] = '\0';
 
-	size_t len = strlen(path);
+	ssize_t len = strlen(path);
 
-	while (len>2)
+	while (len>=0)
 	{
 		if (path[len]=='\\' || path[len]=='/')
 			break;
@@ -118,4 +118,4 @@ Disc* gdi_parse(const char* file)
 
 void iso_term()
 {
-}
\ No newline at end of file
+}