Interesting installation requirements - partitioning scheme for EFI?

[oshunluvr]

I needed to test a specific setup using btrfs as the install filesystem with EFI booting. I built a new VM for the purpose (QEMU if it matters) and the ISO is date April 22nd.

Prior to installing, I manually partitioned the virtual disk with a 512mb EFI partition and the remainder for the install.

Then I ran the installer. selected manual partitioning and selected "format" and BTFS for the install partition. There were no options allowed for the EFI partition. My understanding was this would be all I needed. The install went OK until it was time for Grub to install, which failed. One really does not get any valuable feedback from Ubiquity so went back to my partition scheme and reviewed.

I had selected sector 34 as the start for the EFI partition so I decided that may have been the issue and re-partitioned the disk as before but started the EFI partition at sector 2048. Attempting the install this time I got an immediate error message stating that where was no room for the boot loader to install and that I needed a Boot BIOS partition.

This threw me for a loop. I was of the understanding that one needed EITHER an EFI partition (EF00) or a BIOS boot partition (EF02) but not both.

I partitioned yet again and added the EF02 partition as partition 2 and the installation worked.

My question is: Is having both the EF00 and EF02 partition normal or did something else happen here and cause this? Or was my assumption wrong and both partitions are required?

[Snowhog]

IIRC, I ran into this ‘some time back’. As I learn differently than most, I opted to start fresh and allow the installer to do everything by itself. That let me see how it wanted to partition the disc, and what sizes it wanted.

[claydoh]

Isn't EF02 used on BIOS systems using GPT partitioning (iirc since there is no MBR)? iirc Virt-mamager/Qemu maybe defaults to emulating a BIOS boot, as opposed to an EFI emulation.
I believe that I had to change this setting in virt-manager to change the default to use EFI, or I'd need do so per-machine at install time. No idea what Qemu itself uses by default.

I usually just let the installer figure all that part out, and assign the appropriate flag. Been ages since I used any lower level tools for the purpose, so i a may be wrong here.

[oshunluvr]

Well there you go: I did another VM install and selected "Guided" installation. Obviously you do need both partitions.


I guess I wasn't thinking about the true purpose for these partitions. I incorrectly assumed EF00 replace EF02 functionality. EF02 is needed for GRUB and EF00 is needed for EFI. *buntu uses both EFI and GRUB so there you have it.

[claydoh]

brane fart here, which specific command is showing you the codes?

[claydoh]

I only have two on mine, as my VMs are EFI by default at the moment. Except for the Haiku one.

[Schwarzer Kater]

claydoh

brane fart here, which specific command is showing you the codes?

Probably something like sudo gdisk -l /dev/XXX .

[GreyGeek]

I installed Debian Bookworm as a VM under qemu/kvm earlier this week and ran into the same problem you did. When I checked several videos about installing Debian on YT all of them chose to use "send key" to issue ctl+alt+F2 to open a terminal. From there they did all the partitioning manually, and renamed @rootfs to @ and added the @home subvolume.

I was going to replace my Kubuntu 22.04 with Debian Bookworm sometime this week but decided to keep my current Kubuntu installation because I'm getting too lazy. Installing a new LTS release isn't the fun it used to be. Since I do a fresh install with every new LTS release what ever Debian is offering in 2005 is what I will install.

[oshunluvr]

I only have two on mine, as my VMs are EFI by default at the moment. Except for the Haiku one.

So I wonder what the diff is? Remember I manually formatted the virtual disk with GPT partitioning.

My point being GRUB requires the EF02 parition only on a GPT disk as part of the space GRUB normally uses is taken by GPT.

[claydoh]

I just use EFI for the VM, and use the installer, no manual partitions at all.
Ids your VM running as a 'legacy' install?
A bios boot partition seems to be one used on GPT disks on legacy systems, if I read that stuff correctly.

My manual partitions on my physical neon install:


I think I just used Calamares' partition tools, but I am not at all sure. I could have used Partition Manager from the live session.



And on my 22.04 VM:

This is a basic automatic install, on an EFI virtual machine in qemu via Virt-Manager




good lord our code formatting bbcodes are so bad, lol

[oshunluvr]

The above pic of the VM was an EFI (and thus also GPT) install after selecting "Guided Install - use the whole disk" so the installer did the partitioning. BTW, 0700 is Microsoft Basic Data so probably EFI

[Snowhog]

good lord our code formatting bbcodes are so bad, lol

How so? Which ones?

https://forum.vbulletin.com/forum/vb...ng-attachments

[claydoh]

The Code BBcode produces garbled code using the code buttons ,

as in, when not doing it manually.
And I am sure it is mostly PEBKAC, for sure.

other places seem to have ones that actually paste and keep formatting, or are at least consitent. Others are actually worse (Reddit unless you remember your manual codes)
On one forum, (openmediavualt), you click the code button, and paste into a box in the message area, and the formatted texts is as you see it/paste it

[oshunluvr]

Just because we're talking about it, when I manually make a GPT disk ready for a Legacy install, I create the EF02 partition in sectors 34-2047. An area not used by default anymore for partition alignment. The next partition always begins at 2048 which is the desired starting point for alignment purposes.

[jglen490]

Greetings!

This response is likely immaterial, since I don't use a VM, and I always manually set my partitioning, and I always keep / and /home separate.

This is what mine looks like

john@john-HP-ENVY-x360:~$ sudo gdisk -l /dev/nvme0n1
GPT fdisk (gdisk) version 1.0.8

Partition table scan:
MBR: protective
BSD: not present
APM: not present
GPT: present

Found valid GPT with protective MBR; using GPT.
Disk /dev/nvme0n1: 1953525168 sectors, 931.5 GiB
Model: Samsung SSD 970 EVO Plus 1TB
Sector size (logical/physical): 512/512 bytes
Disk identifier (GUID): CCF88799-68FE-44FF-BF32-D3A771D7E807
Partition table holds up to 128 entries
Main partition table begins at sector 2 and ends at sector 33
First usable sector is 34, last usable sector is 1953525134
Partitions will be aligned on 2048-sector boundaries
Total free space is 3437 sectors (1.7 MiB)

Number Start (sector) End (sector) Size Code Name
1 2048 206847 100.0 MiB EF00
2 206848 102606847 48.8 GiB 8300
3 102606848 1919182847 866.2 GiB 8300
4 1919182848 1953523711 16.4 GiB 8200