diff --git a/xbps-src/xbps-src.sh.in b/xbps-src/xbps-src.sh.in
index 06e77bcea5c..9795196473a 100644
--- a/xbps-src/xbps-src.sh.in
+++ b/xbps-src/xbps-src.sh.in
@@ -171,7 +171,7 @@ check_config_vars()
 			msg_error "couldn't create 'XBPS_MASTERDIR' directory"
 		fi
 	fi
-	export _MASTERDIR="$XBPS_MASTERDIR"
+	[ -z "${_MASTERDIR_FLAG}" ] && export _MASTERDIR="$XBPS_MASTERDIR"
 }
 
 #
@@ -183,6 +183,7 @@ while getopts "Cc:hm:p:" opt; do
 		c) XBPS_CONFIG_FILE="$OPTARG";;
 		h) usage && exit 0;;
 		m)
+			_MASTERDIR_FLAG=1
 			_MASTERDIR="$OPTARG"
 			if [ ! -d ${_MASTERDIR} ]; then
 				mkdir -p ${_MASTERDIR}