Broken system after restore (when `/boot` is on separate partition)

[mwoz123]

Describe the bug
I've (luks encrypted) btrfs / + separate /boot (ext4 & efi).
Due to that /boot dir is not inclueded in backups, this means restoring backup will cause also /boot to be skipped.

Let's say I was on Mint 22 (Ubuntu 24) and tried to restore Mint 21 (Ubuntu 22), the system won't be usable due to mismatch in modules on restored system and in linux image (which was unchanged).

To Reproduce
Steps to reproduce the behavior:

1. On linux that consist of separate /boot partition & root btrfs
2. create a btrfs backup
3. upgrade linux image, purge previous one
4. restore timeshift btrfs backup

Expected behavior
/boot folder to be included/copied to btrfs backup (or other place so it could be restored.

After restore root, timeshift should also restore /boot backup.

Maybe a good idea would be to allow creating "custom script"/hooks to be executed after each backup and another one after each restore (that would allow to copy over the /boot dir) - and might be also usefull for different scenarios.

Screenshots
N/A

System:

• Linux Distribution Name and Version: Mint 22 (Ubuntu 24)
• Desktop - issue it's not about UI - no influence
• Application Version 24.06.3

[mwoz123]

From what I see there's a place for post restore hooks from /etc/timeshift/restore-hooks.d dir but unfortunetely it's executed only for RSync restore, not for BTRFS :(

I as for this scenario also post backup would be required.

[mwoz123]

(In case someone find this usefull)
draft of my setup for /boot on separate partition:

• /etc/timeshift/backup-hooks.d/backup:

#!/bin/bash
echo $TS_SNAPSHOT_PATH
rsync -avr --progress /boot "${TS_SNAPSHOT_PATH}"/@/ --exclude efi

• and /etc/timeshift/restore-hooks.d/restore

#!/bin/bash
echo $TS_SNAPSHOT_PATH
rm -Rf /boot~
rsync -avr --progress /boot /boot~ --remove-source-files --exclude efi
BOOT_SOURCE_BACKUP="${TS_SNAPSHOT_PATH}/@/boot"
rsync -avr --progress $BOOT_SOURCE_BACKUP / --exclude efi 

requires (not merged yet) changes from: #381

[DJCrashdummy]

of course i'm just nitpicking here... but wouldn't be adding --delete to the rsync lines be a tad more efficient (hence suit instant Btrfs snapshots better)? thus you can omit the --remove-source-files option and even the whole rm line.