Comment by arcfour

You can also use SB with your own keys (or even just hashes)...just because Microsoft is the default included with most commercially sold PCs—since most people use Windows on their PCs—doesn't mean SB is controlled by them. You can remove their signing cert entirely if you want. I have done this and used my own.

Plus they signed the shim loader for Linux anyways so they almost immediately gave up any "control" they might have had through SB.