[Solution] Fully dynamic USB auto-restore/save wizard — no /dev/sdb1 hardcoding (GRUB + UUID + script)

[Ace Ventura]

I built a clean, hardware-agnostic Recovery Wizard that works from the USB itself — both RESTORE and SAVE — without any hardcoded device names.

How it works (the flow)

1. GRUB dynamically finds the USB with search --set -f /live/vmlinuz and captures its permanent FAT32 UUID with probe -u $root --set=usb_uuid.
2. The UUID is injected into ocs_prerun1 so Clonezilla can temporarily mount the USB, copy script.sh locally, then unmount.
3. The bash script parses the exact same UUID from /proc/cmdline using a simple sed one-liner, runs fsck.fat, mounts the USB to /mnt/usb, and creates the required symlink /home/partimag → /mnt/usb/zBackup.
4. ocs_live_run then sees the images in the exact place Clonezilla expects → fully automated restore or save.

No LABELs, no static UUIDs in grub.cfg, no device names. Works even with extra hard drives plugged in.

1. GRUB EFI menu entries (add to /boot/grub/grub.cfg on the USB)

menuentry "RESTORE: macmini-preinstall -> AUTO-DISK " --hotkey=r {
    set img="macmini-preinstall"
    search --set -f /live/vmlinuz
    probe -u $root --set=usb_uuid
    linux /live/vmlinuz \
        boot=live union=overlay config noswap nolocales edd=on nomodeset noprompt \
        keyboard-layouts=NONE locales=en_US.UTF-8 vga=788 toram=live,syslinux,EFI,boot,.disk,utils \
        net.ifnames=0 nosplash i915.blacklist=yes radeonhd.blacklist=yes nouveau.blacklist=yes \
        vmwgfx.enable_fbdev=1 ocs_1_cpu_udev scsi_mod.use_blk_mq=0 nvme.poll_queues=1 \
        ocs_prerun="mkdir -p /mnt" \
        ocs_prerun1="mount -U ${usb_uuid} /mnt" \
        ocs_prerun2="mkdir -p /live" \
        ocs_prerun3="cp /mnt/boot/grub/script.sh /live" \
        ocs_prerun4="umount /mnt" \
        ocs_prerun5="sleep 2" \
        ocs_prerun6="bash /live/script.sh" \
        ocs_prerun7="ls /home/partimag" \
        ocs_prerun8="sleep 7" \
        ocs_live_batch="yes" \
        ocs_live_run="ocs-sr -batch -g auto -e1 auto -e2 -r -j2 -p reboot restoredisk ${img} sda"
    initrd /live/initrd.img
}

menuentry "SAVE: AUTO-DISK -> macmini-preinstall" --hotkey=c {
    set img="macmini-preinstall"
    search --set -f /live/vmlinuz
    probe -u $root --set=usb_uuid
    linux /live/vmlinuz \
        boot=live union=overlay config noswap nolocales edd=on nomodeset noprompt \
        keyboard-layouts=NONE locales=en_US.UTF-8 vga=788 toram=live,syslinux,EFI,boot,.disk,utils \
        net.ifnames=0 nosplash i915.blacklist=yes radeonhd.blacklist=yes nouveau.blacklist=yes \
        vmwgfx.enable_fbdev=1 ocs_1_cpu_udev scsi_mod.use_blk_mq=0 nvme.poll_queues=1 \
        ocs_prerun="mkdir -p /mnt" \
        ocs_prerun1="mount -U ${usb_uuid} /mnt" \
        ocs_prerun2="mkdir -p /live" \
        ocs_prerun3="cp /mnt/boot/grub/script.sh /live" \
        ocs_prerun4="umount /mnt" \
        ocs_prerun5="sleep 2" \
        ocs_prerun6="bash /live/script.sh" \
        ocs_prerun7="ls /home/partimag" \
        ocs_prerun8="sleep 7" \
        ocs_live_batch="yes" \
        ocs_live_run="ocs-sr -q2 -batch -j2 -edio -z9p -i 4096 -scs -senc -plu -rm-win-swap-hib -p reboot savedisk ${img} sda"
    initrd /live/initrd.img
}

2. Bash script (/boot/grub/script.sh on the USB — make executable with chmod +x)

#!/bin/bash
# =============================================
# USB Mount folder script - UUID from ocs_prerun
# =============================================

# dynamically read the USB UUID that GRUB passed us from the ocs_prerun1 mount line in /proc/cmdline
usb_uuid=$(cat /proc/cmdline | sed -E 's/.*mount -U ([0-9A-Fa-f-]+).*/\1/' | head -n1)
echo "Detected USB UUID from ocs_prerun: $usb_uuid"

if [ -z "$usb_uuid" ] || [[ ! "$usb_uuid" =~ ^[0-9A-Fa-f-]+$ ]]; then
    echo "ERROR: Could not extract UUID from ocs_prerun line!"
    cat /proc/cmdline | grep -o 'mount -U [^ ]*'
    sleep 10
    exit 1
fi

# create mount folder to use
mkdir -p /mnt/usb

# fix common FAT32 'dirty' errors silently before mounting
fsck.fat -a /dev/disk/by-uuid/${usb_uuid} || true

# Mount as FAT32 (vfat) - 'flush' helps prevent data loss if the USB is pulled early
mount -U ${usb_uuid} -t vfat -o rw,flush,umask=000 /mnt/usb

# create a symbolic link to the mmb folder as /home/partimag
cd /home
rm -r /home/partimag >/dev/null 2>&1 # this is safe even if already mounted as only symbolic link, also -r switch is safe
mmbdir="/mnt/usb/zBackup"
linkmmbdir=(ln -fs "${mmbdir}" partimag)
"${linkmmbdir[@]}"

# validation
if [ -d "/home/partimag" ]; then
    echo "SUCCESS: found folders on FAT32 drive."
    ls -F /home/partimag
else
    echo "ERROR: folders not found – check mount below:"
    mount | grep -E 'usb|partimag'
fi

echo "=== Script finished ==="
sleep 3

Quick setup

1. Burn normal Clonezilla Live to USB (Etcher/Rufus).
2. Add the two menuentries to /boot/grub/grub.cfg.
3. Copy the script to /boot/grub/script.sh and chmod +x.
4. Put your images in the zBackup folder on the USB.
5. Boot → pick RESTORE or SAVE → fully automatic.

Tested on a Mac Mini (EFI) with extra drives plugged in — works perfectly every time.

[Steven Shiau]

Great. Thanks for sharing that.
Another way to do that is, if you accept the have a label for your FAT32 partition on USB stick, say "OCS-REPO", then:
root@cl-20260525-s:~$ blkid /dev/sdd1
/dev/sdd1: LABEL_FATBOOT="OCS-REPO" LABEL="OCS-REPO" ...
root@cl-20260525-s:~$ mount -L OCS-REPO /home/partimag/

[Steven Shiau]

BTW, forgot to mention. You can also use the boot parameter to do that:
ocs_repository="dev:///LABEL=OCS-REPO"
Ref: https://clonezilla.org//fine-print-live-doc.php?path=./clonezilla-live/doc/99_Misc/00_live-boot-parameters.doc#00_live-boot-parameters.doc

[ski-777]

I apologize if I'm writing off-topic information, because in this case we need: GRUB and a USB drive... but then it's also simpler and almost automatic: saving a system backup and restoring from the grub menu. More: https://github.com/ski007/grubzilla

[Steven Shiau]

Cool. Thanks for sharing that.