Automatically update grub on creating Timeshift snapshots

Timeshift's snapshots can automatically be available in the grub boot menu with grub-btrfs:

 https://github.com/Antynea/grub-btrfs#automatically-update-grub

Fixing Watchdog timer infinite boot loop on Arduino Pro Mini (atmega328p 8MHz 3.3V)

Here you can find a detailed explanation of the problem. Unfortunately, the solution provided there works well only for 5V 16MHz configuration. To solve the issue for the 3.3V 8Mhz boards several extra steps are required.

Arduino distro includes precompiled versions of the optiboot bootloader for several most common targets (including atmega328 5V 16MHz). However there is no precompiled binary for the 3.3V 8MHz version.