UEFI boot Ubuntu 12.10 on 520-series

[geoffrey]

I'm having trouble booting straight into Ubuntu 12.10 (64bit) on a GPT disk which also has Windows 8 on it. Windows was installed first, followed by Ubuntu (maybe that was a mistake!). I have the latest BIOS from Lenovo, 1.39 (29th Oct 2012).

Both Windows and Ubuntu created entries in NVRAM, which can be seen in the BIOS setup, and also when I press F12 on bootup. I can boot Ubuntu from the F12 menu -- in that case the computer boots up Grub2 with no problems, and then from Grub2 I can either boot Ubuntu or Windows 8 (actually, to get Windows 8 to boot from Grub, I had to run boot-repair in Ubuntu because the standard Ubuntu dual-boot install didn't get this right). But if I set the NVRAM "Ubuntu" entry as the first (default) entry in the BIOS, then on bootup the W520 can't boot straight into Grub2, and instead presents me with the startup choices screen (the same one you get if you press F12). Manually choosing the Ubuntu entry boots into Grub2 OK. The same behaviour occurs if I disable the "Windows Boot Manager" entry in BIOS, and even if I delete it -- I am forced to choose the Ubuntu entry manually, it won't boot automatically into Grub2. On the other hand, if the Windows entry is the default in BIOS, then the computer boots straight into Windows. (NB Don't delete the Windows entry if you can't boot Windows from Grub!!)

I've tried leaving the "Windows" entry as default and replacing the .efi file it points to (bootmgfw.efi in the /EFI/Microsoft/Boot/ folder of the EFI system partition) with the Ubuntu file (grubx64.efi from the /EFI/ubuntu/ folder). But the Lenovo BIOS seems to realize what I'm up to and won't let me boot it automatically (it forces me to select the entry). In this configuration, selecting the "Windows Boot Manager" entry boots into Grub2, as expected. But I don't get why the BIOS won't boot straight to Grub and forces me to choose it manually.

My ideal is to get the Grub2 menu to appear automatically at boot time, from which I can then choose either Ubuntu or Windows. I know I can do this with the F12 bypass, so "why bother?". But it's a matter of principle. Windows shouldn't be the only operating system to boot up automatically.

Any thoughts or experience with setting this up correctly?

[geoffrey]

As often happens, straight after posting I thought of the obvious solution that was literally staring me in the face (although it still has problems under Windows 8 ).

I was renaming the wrong file. The Lenovo BIOS (or, more accurately, EFI Firmware) looks for the file bootx64.efi in /EFI/Boot/ on the EFI System Partition. If it's the same file as the default set in the BIOS Boot menu (i.e. the first on the list), then it boots it automatically. My guess is that if a different file is set as default, the BIOS is programmed to seek user confirmation first, so it throws up the F12 menu even if F12 wasn't pressed.

Looking at the size of the file in my /EFI/Boot/ folder, it was clearly the Microsoft boot loader. I renamed it winbx64.efi (to have as a backup) and copied the Ubuntu bootx64.efi to this folder. Now the W520 boots straight into Grub2, as expected.

The one caveat I have discovered so far is that this configuration breaks the Windows 8 rapid shutdown/startup feature. Windows 8 actually does a core "hibernate" when you request shutdown, i.e., it throws out the majority of RAM and just writes to disk a small core of RAM needed to start up again rapidly. When you restart into Grub2 after such a shutdown and load up the Windows Boot Manager from Grub, Windows detects that you may have been in a different operating system and dumps the resume file before offering its own menu. There's probably a way round this -- to get Grub2 to check for the existence of whatever flag is set by the system to indicate its hibernation state and load a different .efi. But that's a minor problem I haven't investigated further at the moment. Personally I tend to use a full restart rather than shutdown if I intend to boot into Ubuntu from Windows, so it's only a small irritation. If anyone can shed light on it, that would be brill. But main problem solved.

PS, anyone wanting to try this (but be very careful because you could break your boot and be locked out of Windows and Linux), the EFI partition is already mounted under /boot in Unbuntu. If you want to do the same in Windows, you need to open an Administrator Command Prompt, run diskpart, list volumes, select the FAT32 volume (select vol x), assign (to mount the partition and get a drive letter), then exit diskpart, and you can then manipulate the files in the Command Prompt shell. Access in Explorer is blocked.