[Feature] Add img backup before flashing

[jimsterino98]

Is your feature request related to a problem?

No response

Describe the solution you'd like

Basically similar to kernel flasher, would be good to back up boot.img before flashing the ak3 zip.

Describe alternatives you've considered

No response

Additional context

A cool feature would be, if someone forgets to back up current .img and just flashes it, get wksu to automatically back it up. Then when the user reboots, if something happens and if the person gets stuck in a bootloop, it can somehow detect it and automatically revert back to previous img. That possible?

[fatalcoder524]

Then when the user reboots, if something happens and if the person gets stuck in a bootloop, it can somehow detect it and automatically revert back to previous img. That possible?

This is technically not possible for all cases!

Issues with this are:

1. Module-based bootloop can trigger this feature and revert the kernel. That might cause instability between ksud and the kernel and cause more issues. Especially for people who only use stable versions.
2. The case where the kernel build had an issue, and some system kernel module doesn't even allow booting. The way you want implementation is already implemented in the bootloader, where multiple boot failures trigger a slot change.

So Technically this doesn't make sense!

The only place this makes sense is the case where: User is installing for the first time, and he forgot to backup stock boot.img. Even in this case, Its only usable if,

• Device boots, and he needs a stock boot.img for the future.
• He has copied the boot.img to his PC for backup without forgetting it.

If the user has access to custom recovery, and the kernel is not fully nuked that even the recovery doesn't work, then they can just flash the previous working AK3 zip they trust.