diff --git a/tools/autobuild/build.sh b/tools/autobuild/build.sh
index bf999f80..627a6273 100755
--- a/tools/autobuild/build.sh
+++ b/tools/autobuild/build.sh
@@ -9,7 +9,7 @@ ONL="$(realpath $(dirname $AUTOBUILD_SCRIPT)/../../)"
 # Default build branch
 BUILD_BRANCH=master
 
-while getopts ":b:s:d:u:p:vc78" opt; do
+while getopts ":b:s:d:u:p:vc78r:" opt; do
     case $opt in
         7)
             ONLB_OPTIONS=--7
@@ -32,6 +32,9 @@ while getopts ":b:s:d:u:p:vc78" opt; do
         v)
             set -x
             ;;
+        r)
+            export BUILDROOTMIRROR=$OPTARG
+            ;;
         *)
             ;;
     esac