TLDR: Canonical asked some copyright attorneys who specialize in software licensing rights if the GPL would create issues. They said it could, and that Canonica

TLDR: Canonical asked some copyright attorneys who specialize in software licensing rights if the GPL would create issues. They said it could, and that Canonical could but probably would not be liable if such issues arose. Canonical decided that the easiest, most pragmatic thing to do was to switch bootloaders and not have to deal with this issue at all. GRUB is a decent bootloader, but it's not sufficiently better than the alternatives to justify the additional costs keeping it would have imposed. (These additional costs would likely not be actual expenditures, but reserves booked pursuant to accounting standards).