I'm guessing the GRUB timing thing is probably due to some kernel module that I haven't properly loaded, and I should just figure out what the module is and always load it instead of scanning. But the BIOS hang is baffling me. It even happens if I unplug the VGA monitor.
I have a very strange bug with a dual-head desktop. One monitor is VGA, the other DisplayPort. If the DP monitor is plugged in @ poweron, BIOS boot hangs. If it's NOT plugged in before GRUB boots, it's never detected by udev. So, 10sec window to plug it in. WTF?