diff --git a/cfg/osic1p.cfg b/cfg/osic1p.cfg
index b05eeb3d5..fd9aa604e 100644
--- a/cfg/osic1p.cfg
+++ b/cfg/osic1p.cfg
@@ -10,7 +10,7 @@ SYMBOLS {
 }
 MEMORY {
     # for size of ZP, see runtime/zeropage.s and c1p/extzp.s
-    ZP:       file = "", define = yes, start = $0002, size = $001A + $0006;
+    ZP:       file = "", define = yes, start = $0002, size = $001A + $0020;
     HEAD:     file = %O,               start = $0000, size = $00B6;
     RAM:      file = %O, define = yes, start = %S, size = __HIMEM__ - __STACKSIZE__ - %S;
 }