did lots of work

gen_image.sh

@@ -5,10 +5,12 @@ if [[ $(id -u) -ne 0 ]]; then
   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)"
+image=mdos.img
+
+rm -f $image
+fallocate -l 100M $image
+echo -e "o\nn\n\n\n\n\nw\n" | fdisk $image
+loopdevice="$(losetup -P --show -f $image)"
 looppart=${loopdevice}p1
 mkfs.ext4 $looppart
 
@@ -16,9 +18,18 @@ mkdir -p mountdir
 mount $looppart mountdir
 cd mountdir
 tar --xattrs -xpf ../fs.tar
-grub-install --target=i386-pc --boot-directory="$PWD/boot/grub" $loopdevice
+grub-install --target=i386-pc --boot-directory="$PWD/boot" $loopdevice
 cd ..
+
+## generate grub.cfg (since linux 3.8 32-bit MBR "NT disk signatures" are allowed)
+uuid=$(fdisk -l $image | grep "Disk identifier" | cut -d " " -f 3 | cut --complement -c 1,2)-01
+echo -e "linux /boot/bzImage root=PARTUUID=$uuid\nboot" > "mountdir/boot/grub/grub.cfg"
+
 umount mountdir
 sync
 rm -rf mountdir
 losetup -d $loopdevice
+
+if [[ -n $SUDO_UID ]]; then
+  chown $SUDO_UID:$SUDO_GID $image
+fi