diff --git a/cfg/c64-overlay.cfg b/cfg/c64-overlay.cfg
index e88bffe00..0f42434ad 100644
--- a/cfg/c64-overlay.cfg
+++ b/cfg/c64-overlay.cfg
@@ -14,7 +14,7 @@ MEMORY {
     ZP:       file = "", define = yes, start = $0002,                size = $001A;
     LOADADDR: file = %O,               start = %S - 2,               size = $0002;
     HEADER:   file = %O, define = yes, start = %S,                   size = $000D;
-    MAIN:     file = %O, define = yes, start = __HEADER_LAST__,      size = __HIMEM__ - __HEADER_LAST__;
+    MAIN:     file = %O, define = yes, start = __HEADER_LAST__,      size = __OVERLAYSTART__ - __HEADER_LAST__;
     BSS:      file = "",               start = __ONCE_RUN__,         size = __OVERLAYSTART__ - __STACKSIZE__ - __ONCE_RUN__;
     OVL1ADDR: file = "%O.1",           start = __OVERLAYSTART__ - 2, size = $0002;
     OVL1:     file = "%O.1",           start = __OVERLAYSTART__,     size = __OVERLAYSIZE__;