diff --git a/custom_boot.sh b/custom_boot.sh
new file mode 100755
index 0000000..5338184
--- /dev/null
+++ b/custom_boot.sh
@@ -0,0 +1,46 @@
+#!/usr/bin/bash
+
+usage()
+{
+    echo "Usage: $0 [ -d dirname ]" >&2
+    echo "ex: $0 -d /zones/boot/boot-20220113T011608Z"
+    exit 1
+}
+
+while getopts ":d:" opt;
+do
+    case "$opt" in
+        d)
+            DIR=$OPTARG
+            ;;
+        \?)
+            echo "Error: Invalid Option: -${OPTARG}" >&2
+            usage
+            ;;
+        :)
+            echo "Error: -${OPTARG} requires an argument."
+            usage
+            ;;
+        *)
+            usage
+            ;;
+    esac
+done
+
+shift $((OPTIND -1 ))
+
+if [ -z ${DIR} ]; then
+    usage
+fi
+
+mkdir -p $DIR/bootfs/etc
+cp /etc/system $DIR/bootfs/etc/
+
+echo 'set ngroups_max=1024' >> $DIR/bootfs/etc/system
+
+cat << EOF >> $DIR/loader.conf.local
+etc_system_load=YES
+etc_system_type=file
+etc_system_name=/boot/bootfs/etc/system
+etc_system_flags="name=/etc/system"
+EOF