UEFI Build Test

[gold_finger]

I may be off topic but I still don't understand this problem. I installed LL 2.6 on this new computer with the help of ASUS. I did not understand how to change the boot order since it does not have the good old BIOS so it would boot from a DVD (or USB) before the hard drive. Once they talked me through changing the boot order, LL installed with no problems. Would a UEFI build change the boot order?  :-\

In a word -- No.


Some basics:

After powering on the computer, firmware built into the motherboard handles the initial boot process.  It performs basic tests of components to make sure all is well, then passes on responsibility to complete the boot process to operating system boot loaders on the hard drive.  On older computers that firmware was called BIOS = Basic Input/Output System.  Most new computers now use firmware called UEFI = Unified Extensible Firmware Interface.  UEFI has expanded capabilities over the older BIOS firmware.

Hard drives can be formatted to use either MBR/(msdos) partitions, or GPT partitions.  MBR partitioned drives can only have 4 primary partitions, or 3 primary partitions and one extended partition that can then house multiple logical partitions to overcome the 4-partition limit.  The first 512 bytes on an MBR drive contain the Master Boot Record (MBR) and the partition table for the drive. The MBR holds initial boot loader code for installed operating system(s).  Most BIOS-based computers use MBR drives and after initial P.O.S.T. (Power On Self Test), the firmware points to the MBR of the hard drive to boot the installed operating system(s).  (Only one operation system can have initial boot code in the MBR.  The initial boot code there points to second stage boot code located elsewhere on the drive to complete the boot process and/or offer choices to boot multiple operating systems if others are installed.)

In contrast, most new computers with UEFI firmware use GPT partitioned drives.  GPT drives don't have a 4-partition limit and have other advantages over MBR drives.  Also, boot loader code is placed on a special "EFI System Partition" (ESP) instead of on the MBR and UEFI firmware points to that partition to finish booting an operation system after initial system checks are done.  The ESP can hold boot loader files for multiple operating system.  Typically the UEFI firmware will provide the user with a way to specify which operating system to use as the "default" system when booting the computer.

Not all UEFI firmware is implemented the same way -- it varies from one manufacturer to the next.  Read your computer's user manual and/or boot into the UEFI settings menu and have a look around at the different options available.  Eg.  If you have Windows on the computer and later install a Linux distro, sometimes the firmware will automatically make the last installed system (Linux) the default OS to boot into.  Others may keep Windows as the default and not show a Linux choice until you manually change that in the settings.


Now, getting back to what you stated about installing LL after talking to Asus.  I'm going to make a guess that you installed LL as the only OS on the computer and wiped-out Windows.  Is that correct?

The reason I say that is because I highly doubt that they would have known how to guide you through a UEFI dual-boot install with LL and Windows.

My guess is that you installed LL in Legacy mode, not UEFI mode.  Assuming that Windows was installed originally in UEFI mode, that would mean that the hard drive was using GPT partitions.  If you installed LL in Legacy mode, dual-booting would not work without you having to manually change boot modes depending on which OS you were trying to boot.  Since you didn't state having to do that, I'm assuming that you only have LL on the computer.

You can confirm that LL was in fact installed in Legacy mode (not UEFI mode) by running this command in a terminal:

Code:

sudo parted --list

Assuming the line "Partition Table =" says "gpt", you will likely see a small (1-16MB), unformatted partition labeled "bios_grub", (or "bios_boot") as part of the output.  The presence of that partition would confirm that you have a Legacy mode install.  (That is not a problem and does not affect the operation of LL.  I'm just pointing out that you probably don't have a UEFI mode install.  In all likelihood, the Asus people had you change the UEFI settings to use CSM/Legacy instead of UEFI.)

If "Partition Table = msdos", then you also have a Legacy mode install of LL.

P.s.
If you are dual-booting with Windows, then my guess is that both OS's are installed in Legacy mode.