diff --git a/common/xbps-src/shutils/chroot.sh b/common/xbps-src/shutils/chroot.sh
index b880d4151d2..9c36a173255 100644
--- a/common/xbps-src/shutils/chroot.sh
+++ b/common/xbps-src/shutils/chroot.sh
@@ -5,7 +5,7 @@
 chroot_init() {
     mkdir -p $XBPS_MASTERDIR/etc/xbps
 
-    : ${XBPS_CONFIG_FILE=/dev/null}
+    : ${XBPS_CONFIG_FILE:=/dev/null}
     cat > $XBPS_MASTERDIR/etc/xbps/xbps-src.conf <<_EOF
 # Generated configuration file by xbps-src, DO NOT EDIT!
 $(grep -E '^XBPS_.*' "$XBPS_CONFIG_FILE")