I disassembled my Acer Aspire ES1 to upgrade the RAM, and in doing so unplugged the battery cable. This must have pissed off the CMOS and I get stuck with a “Secure Boot Fail” loop because my grub2 EFI install isn’t set up for secure booting. And for some unknown reason, F2 doesn’t work and the Acer logo never even appears. Even pressing the reset button on the motherboard has no effect, nor does removing the CMOS battery.
To fix this, I grabbed a copy of the Ubuntu x64 install DVD and wrote it to a USB stick, and booted off of that since it is secure bootable. From there, I exited to the grub command prompt with Ctrl-C and typed:
That brought me to the UEFI (BIOS) setup screen and I was able to again disable secure boot: see my previous post for that.