Okay, the 20161005.1 ISOs seem to have done the trick. Tested the desktop and server ISOs under QEMU+OVMF, plus tested the desktop ISO on a slew of UEFI hardware. No issues encountered shim-wise.
I'll test the server ISO on UEFI hardware shortly, but there are a few other things I need to finish up first.
Okay, the 20161005.1 ISOs seem to have done the trick. Tested the desktop and server ISOs under QEMU+OVMF, plus tested the desktop ISO on a slew of UEFI hardware. No issues encountered shim-wise.
I'll test the server ISO on UEFI hardware shortly, but there are a few other things I need to finish up first.
Big thanks to everyone who helped on this!