Clean-Ubiquity is an addon for Ubiquity. It automatically performs a backup of the bootsector that is altered by Ubiquity, and links it with the UUID of the new OS.

This can be extremely useful if the computer is MBR-locked. MBR-lock is a system that can be found on some OEM computers with pre-installed Windows. It is (was?) put in place by some manufacturers in order to fight against Windows piracy, by preventing or making difficult the use of a Windows with a different version from the one that was originally on the computer. MBR-lock is now forbidden in some countries (e.g. France), so it should not be on recent computers. Basically, this system uses data written on the motherboard and/or the MBR. If the MBR has been altered (e.g. by GRUB), this system will detect it and prevent Windows (or the entire computer) to boot.

Clean-Ubiquity needs 2 preseeds integrated during the ISO building.