Instruction for custom partitioning during Ubuntu install anywhare?

[Liam Proven]

On Fri, 21 Jan 2022 at 20:37, Bo Berglund <bo.berglund at gmail.com> wrote:

> This HP "BIOS" does not look anywhere like the Lenovo one I discussed here a
> while ago, but I tried to find and set the relevant items as best I could to
> boot to USB.
[...]

But you haven't answered my question. :-(

If it is a UEFI machine, or if it is set to boot UEFI first, then you
*must* configure the hard disk UEFI style.

This has bitten me before.

That means:

* You _must_ have an EFI System Partition (ESP)
* It must be set as that type, formatted FAT32, and marked bootable.
* Ubuntu must know where it is and that it is the ESP. You may have to
tell it while partitioning.

If you do not have a working ESP, and you try to install the "old" way
with GRUB in the MBR, the PC will not boot. That method doesn't work
with UEFI.

The easiest way to get a working ESP on a UEFI machine in case of
problems is to install Windows 10 on it. :-(

That is why I asked about the boot *order*. If you have both and both
are enabled _but BIOS boot is tried first_ then the old GRUB-in-MBR
method should work.

But -- caveat! -- here is a bug in Ubuntu since 20.04 or so: it
creates an ESP partition even on BIOS systems. It is not needed and it
doesn't do anything, but it makes one anyway, and if you remove it,
Ubuntu gives an error and won't finish installing correctly.

I have filed a bug:
https://discourse.ubuntu.com/t/20-10-needs-esp-on-bios-systems-existing-confirmed-unassigned-bug/21789

It hasn't been fixed properly and the bug came back in 21.04. :-(

If you have partitioned the disk with GPT, there is no difference
between primary and secondary partitions any more. GPT does not have
that distinction. But since you mentioned a partition inside an
extended partition, I guess it is partitioned with MBR.

If the SSD is NVMe, you _must_ use GPT, but we covered that in our
previous thread.

I think it is a model of this?

https://support.hp.com/us-en/document/c06047054

It mentions NVMe drives as an option, so I think it _must_ have UEFI.
So the question is, which boot mode is it using -- UEFI then BIOS, or
BIOS then UEFI?

The route I used on my old office PC was:

* Partition with and install Win10, in a fairly small partition.
* Dual-boot with 2+ Linux distros, allowing them to use the Windows ESP.

This was before I discovered the question of firmware boot type and priority.

-- 
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