0

As per subject, would like to upgrade my 20.04 install from BIOS to UEFI. I have to do this to leverage re-BAR to then have a quicker/better communication between my videocard and RAM.

I read that I should have to:

  1. Convert my main disk from MBR -> GPT (would I still be able to boot in BIOS mode after this? Should I simply use gdisk?)
  2. Resize my current / partition from 128 GiB to 127 and leave 1 GiB at the beginning for a FAT32/EFI
  3. Mark to first partition to be EFI (Is it the case? How should I do this?)
  4. Install the new (.efi) boot loader on there, pointing to my EXT4 / partition (How can I do this?)
  5. Ask the motherboard to use EFI instead of BIOS

Am I correct in my understanding? How con I implement points 3 and 4?

I did not mention backups etc etc, but I got a 2 TiB external SSD (should be a fast USB) and I plan to dd if=/dev/nvme1n1 of=/<my temp mount>/backup.img (to do a backup of my 1 TiB main nvme disk - when unmounted of course).

Another strategy would be to convert from MBR -> GPT (still in BIOS mode if possible) and then perform a fresh Ubuntu reinstall preserving /home partition on nvme1n1. But then I would need to have both my user ids preserved (I have other 4 drives with proper permissions setup and wouldn't want to chown all the way around my filesystem).

What's your recommendation?

Thanks!

Ps. I will upgrade to 22.04 as soon as it will be deemed safe.

Emanuele
  • 636
  • 2
    I do not like dd for backups. And you cannot easily restore MBR install to gpt. You can use gpt to boot in BIOS mode, but gpt needs a tiny 1MB unformatted partition with bios_grub flag. If you convert, at minimum you need to reinstall grub & update all UUIDs in fstab. You should also export list of installed apps & rsync data on boot drive. And any server apps in / and perhap some settings in /etc. I suggest new clean install & restore from backup, but it may depend on how you backed up data & configuration of drive. Be sure to create users in same order as actually 1000, 1001, 1002, etc – oldfred Jul 25 '22 at 20:09
  • https://askubuntu.com/questions/913397/how-to-change-ubuntu-install-from-legacy-to-uefi – Rinzwind Jul 25 '22 at 20:17
  • @Rinzwind looks like a duplicate to me. :) – user68186 Jul 25 '22 at 20:52
  • 1
    What does mode (UEFI vs. legacy) or disk partitioning (GPT vs. MSDOS) have to do with PCI bus enumeration? – ubfan1 Jul 25 '22 at 21:03
  • @ubfan1 It's about resizeable BAR – Emanuele Jul 25 '22 at 21:27
  • No, it's not. It's about reading something complex which is targeted to engineers only and misunderstanding it completely. – ChanganAuto Jul 25 '22 at 22:59
  • I have just finished updating my wife's Ubuntu disk similar to this: https://askubuntu.com/questions/1403792/how-to-create-a-full-install-of-ubuntu-22-04-to-usb-device-step-by-step. But with internal disks. The method will boot either BIOS or UEFI. I reused boot, /home and NTFS data partitions from her previous disk and overwrote Ubuntu 18.04 with 22.04. Previously the disk was formatted MSDOS, now it is GPT and I can now boot Windows from GRUB. – C.S.Cameron Jul 25 '22 at 23:05
  • Boot-Repair will not create an ESP, so you must have the EFI system partition before running boot repair. – oldfred Jul 25 '22 at 23:12
  • @ChanganAuto https://www.nvidia.com/en-gb/geforce/news/geforce-rtx-30-series-resizable-bar-support/ – Emanuele Jul 25 '22 at 23:20

0 Answers0