Booting Ubuntu on a UEFI computer

[Bob]

** Reply to message from Rashkae <ubuntu at tigershaunt.com> on Sun, 18 Feb 2018
18:21:31 -0500

> EFI partition and bios-grub are mutually exclusive.  This does not mean
> that both can't exist on the same drive, but only one will be used
> during the boot process.
> 
> 
> bios-grub paritition is used with legacy, pre-EFI boot BIOS.  In theory,
> the CSM should also be able to load boot code from bios-grub.  In
> practice, the one time I tried this it would not work.  I didn't really
> trouble shoot it, as it was more or less irrelevant.
> 
> bios-grub exists because of the new hard drive partition scheme, GPT.
> When a large capacity hard drive is formatted GPT, or if you just want
> the greater flexibility of GPT partitioning, GRUB can no longer embed
> boot code in unused space the way it used to.  In short, if your hard
> drive is partitioned with GPT partitions, you will need a bios-grub
> partition to boot with a legacy, pre-efi BIOS.
> 
> 
> Here is where I think you are getting into trouble.  For Ubuntu
> installer to properly configure EFI boot, you have to boot the install
> CD with EFI.  With CSM enabled, your motherboard will allow you to boot
> the CDROM in legacy mode, in which case, the installer will not load the
> kernel modules needed to install EFI boot environment.  I have even seen
> many motherboards that boot CDROM in legacy mode by default.

That was the problem.  With CSM enabled the first item in the boot menu was the
CD in legacy mode.  The CD in EFI mode was the fourth entry.  This required me
to hold the Esc key when I power on to get the boot menu and select the EFI CD
to install Ubuntu.


> When your system is booting, there should be a way to choose a one time
> boot media.  In your choices, you should see for an option that
> explicitly offers UEFI on the CDROM.  If it's too obscure, you can try
> just disabling the CSM, (and therefore, no legacy boot whatsoever.)

Thanks

-- 
Robert Blair


The ultimate result of shielding men from the effects of folly is to fill the world with fools.  -- Herbert Spencer, English Philosopher (1820-1903)