Unable to boot Linux / Windows as there are no boot entries in the BIOS

Question

I have Asus N56D laptop with Windows 8 pre-installed in EFI mode. I installed Linux Mint 15 dual boot and got it working with the Boot-Repair utility. Everything was going fine until I decided to install Karora Linux. I was unable to boot Karora Linux in UEFI mode hence I enabled Legacy BIOS mode and installed Karora successfully. But when I reboot the system neither Karora nor Windows 8 is booting.

I went to BIOS to check the boot order I did not see any boot option entries like "Windows Boot Manager", rEFInd, etc.

At least to get Windows 8 working I followed approach of rebuilding bcd like below with no luck.

bcdedit /export c:\bcdbackup
The operation completed successfully.
attrib c:\boot\bcd -h -r -s
ren c:\boot\bcd bcd.old
bootrec /rebuildbcd
Scanning all disks for Windows installations.

Please wait, since this may take a while...

Successfully scanned Windows installations.
Total identified Windows installations: 0

It did not find any Windows 8 installation :( although I have it on my C:\

I checked in GParted (launched from Karora live USB) that my EFI partition is still intact and has boot flag. Also it has folders like rEFInd Microsoft etc.

Please guide me to solve this issue. I am not able to use my laptop as I've messed up badly.

Answer 1

You need to set your system back to EFI mode. If you boot in BIOS mode, the EFI variables are NOT available to the OS (regardless of it being Windows or Linux).

If you boot to linux, you can look at /sys/firmware/efi/efivars and /sys/firmware/efi/vars/ to see if you are in EFI mode successfully or not.

Windows supports UEFI-GPT boot or BIOS-MBR boot only, and not UEFI-MBR or BIOS-GPT boots.