diff -r 4108bc324a08 sys/src/cmd/dossrv/dossubs.c
--- a/sys/src/cmd/dossrv/dossubs.c	Sun Apr 05 03:05:06 2020 +0200
+++ b/sys/src/cmd/dossrv/dossubs.c	Sun Apr 05 03:37:27 2020 +0200
@@ -1683,7 +1683,8 @@
 {
 	Dosbpb *bp = xf->ptr;
 	Iosect *p;
-	int n, i, k;
+	int n, i;
+	vlong k;
 
 	n = bp->freeptr;
 	for(;;){