script works

gen_image.sh

@@ -0,0 +1,24 @@
+#!/bin/sh
+
+if [[ $(id -u) -ne 0 ]]; then
+  echo "run as root"
+  exit 1
+fi
+
+rm -f mdos.img
+fallocate -l 100M mdos.img
+echo -e "o\nn\n\n\n\n\nw\n" | fdisk mdos.img
+loopdevice="$(losetup -P --show -f mdos.img)"
+looppart=${loopdevice}p1
+mkfs.ext4 $looppart
+
+mkdir -p mountdir
+mount $looppart mountdir
+cd mountdir
+tar --xattrs -xpf ../fs.tar
+grub-install --target=i386-pc --boot-directory="$PWD/boot/grub" $loopdevice
+cd ..
+umount mountdir
+sync
+rm -rf mountdir
+losetup -d $loopdevice