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Move boot SSD from BIOS motherboard to UEFI motherboard?

cn flag

I'm (still) running 18.04 on a old BIOS-based motherboard.

Back in the day when all motherboards were BIOS-based, upgrading was as simple as moving a HDD from one system to another. Is it still that simple when doing a to-UEFI migration? (The current boot process probably uses UUID, but I'm not sure; computer just died: after 6-7 seconds, it powers back down.)

guiverc avatar
cn flag
It'll depend if your system was installed with ESP & the ESP was written on that drive & correctly. For recent releases; some ISOs do not (*by default*) write ESP when BIOS machine is detected (*as it isn't required*) whilst others always write an ESP (*it's just ignored & its only a small amount of wasted disk space*) so it'll depend on what ISO you installed with, PLUS what options were used by install as to whether or not you can just move your drive across (*on all ISOs you can force creation of ESP or prevent ESP from being written desktop ISOs anyway*). You gave no such details.
RonJohn avatar
cn flag
@guiverc it's been quite a few years since I installed 18.04 on that SSD, so don't remember if the 18.04 ISO mentioned anything about ESP.
guiverc avatar
cn flag
If you don't have the ESP (EFI System Partition) the drive will not boot on an uEFI/Secure-uEFI machine; as the ESP replaced the MBR used by legacy 1982 & later BIOS machines. You can usually spot it (ESP partitions are small & mandated to be a specific formats to reliably work); or you can watch for clues on certain commands, eg. a `sudo grub-install /dev/sda` on my existing box tells me "*Installing for x86_64-efi platform.*" which tells me I'll have an ESP (the box actually has two; untouched & unused windows ESP that I considered too small; plus one used by both my Ubuntu installs).
RonJohn avatar
cn flag
@guiverc (My system is dead so I can't check.) Does this mean I'll have to reinstall (presumably using 22.04) once I'm on the new system?
guiverc avatar
cn flag
I was just trying to give clues on what to look for, ie. `blkid` for mine shows `/dev/sda1: UUID="86FB-0B32" BLOCK_SIZE="512" TYPE="vfat" PARTLABEL="EFI system partition" PARTUUID="174dc261-8988-4f64-b680-9cbc94e6d876"` being the ESP for the windows 11 I don't use, and `/dev/sda5: LABEL_FATBOOT="UBU_ESP" LABEL="UBU_ESP" UUID="FE36-F64F" BLOCK_SIZE="512" TYPE="vfat" PARTUUID="f6a93984-cd3b-6c41-bbd2-5333f364f592"` being ESP I created during install of the two Ubuntu OSes on this box (last month when my old BIOS box died; I didn't try & re-use drive; just copied the data I wanted from backups)
RonJohn avatar
cn flag
@guiverc thanks.
guiverc avatar
cn flag
Ubuntu Desktop ISOS for recent releases create an ESP even if not required (*though using some install options can cause it not to be created*), but in comparison Lubuntu ISOs from 18.10 & later would not (*if using BIOS*), but I can't recall what was created on 18.04 as that was too long ago for me to be reliable. I'd look and see
RonJohn avatar
cn flag
@guiverc is the ESP partition "large" (like 512MB), and visible by gparted? If so, then I don't have it on my system.
guiverc avatar
cn flag
My windows ESP was 100MB (*what I considered too small for 3x OSes; I'll only wipe the windows 11 when I need the disk space then have 2xUbuntu*) thus I created a larger 512MB ESP. ESP size is often 100MB or 300MB with 512MB on the larger end (*common for more recent installs; for smaller is more common for older installs or single-OS*)
RonJohn avatar
cn flag
@guiverc however large it "should" be, it's large enough that I'd notice it in the partition table... This answers my question.
RonJohn avatar
cn flag
@guiverc the SSD from my old BIOS mobo booted right up in my UEFI mobo.
guiverc avatar
cn flag
Thanks for letting me/us know; Ubuntu ISOs for some time, have by default created an ESP so that will occur; however not all do (eg. *Lubuntu in my example that creates it only if booted using uEFI mode prior to install; I'm using Lubuntu as example here only*).. Installation impacts this to a large extent (ie. *which includes ISO used & options used during install*). If your problem is solved; you can write up your own answer; feel free to include any details I/others provided too esp. if helpful (*ref. me/others too if you wish*) but it can be largely based on what you did & your solution
RonJohn avatar
cn flag
@guiverc I don't see anything that looks like an ESP on my boot disk. The only partitions are fat32 `/dos`, ext4 `/`, linux-swap and xs `/home`.
guiverc avatar
cn flag
The ESP is the EFI System Partition; usually small vFAT partition and is necessary to boot on a uEFI system if its not in legacy/CSM mode (when in *legacy* mode it'll boot the same as any BIOS computer from 1982 & later as per standard if x86/IBM PC compatible architecture). The ESP is the *newer* standard that replaced the original IBM standard; instead of the reserved MBR on the disk that is booted; the ESP partition is read & used allowing for more than 512 bytes of code to be included...
RonJohn avatar
cn flag
@guiverc "if its not in legacy/CSM mode". Ah... I bet my mobo is configured by default to be in legacy mode.
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