However, the stick does not boot. I get a black screen without a GRUB menu. I'm not seeing what package has changed that would affect this. Last time it worked for me was beta TC4.
Works with TC5, does not work with TC6. Regression. Checked grubx.64.efi between the two ISOs and they are identical. However, the bootx64.efi's have different sha256sums for some reason. I think this file is shim.efi, but I don't see a recent change in the shim package to account for this. Updated the bug with this info, leaving it set on livecd-tools.