I shifted Windows 8 based laptop to boot in Bios Legacy mode just to be able to use a USB Key with a 32 bits Ubuntu saucy on it. Worked fine. I tried an install on a fresh GPT partition and it worked fine. However...

Now I cannot access the BIOS anymore. The F1 or Enter key (that are supposed to lead me to BIOS setup, or to interrupt the standard boot respectively) just... do nothing. Ubuntu (32 bits) boots up immediately.

Is there any way to reenter the BIOS. I would like to do a clean UEI based 64 bits install now or even access Windows 8. But I cannot even turn back the boot to UEFI mode :-(

Several people seems to have the same issue and even clering the CMOS (by removing the internal RTC backup battery) does not help. It just clears the RTC, the BIOS is using non volatile memory.

1 Answer

I've heard of this problem, but I've never experienced it myself. In the case I heard of, the cause seemed to be that the firmware was using an entry in its boot manager to activate the ability to enter the firmware setup tool. The boot manager list is stored in NVRAM and is manipulated by tools like Linux's efibootmgr, an EFI shell's bcfg, or even the firmware's built-in user interface. When that list was modified in certain ways, the entry to access the firmware user interface went away. IIRC, the person who had this problem was able to restore the thing by resetting the NVRAM -- but you say you've tried that to no avail. Still, it might be worth trying again.

You might try unplugging all your disk devices and booting the computer. With any luck, this will cause the firmware to enter its setup utility, and if you're very lucky, that option will remain accessible when you reboot with your disks attached.

Another option might be to use a tool, such as gummiboot or my rEFInd, that includes an option to reboot the computer into its setup utility. There are USB flash drive and CD-R images of rEFInd that should be easy to test. Unfortunately, not all EFIs provide this feature, so if yours doesn't, this obviously won't work. You'll also need a way to test rEFInd. This is easy enough if you can get to your boot manager menu, but if your firmware is really badly inaccessible, you might need to install the tool on your hard disk to get anywhere, and that's both more hassle and more risk.

If all of this fails, return the computer; this type of problem constitutes a design defect, IMHO.