On bootup grub fails, fix but on restart fails again - include pastebin boot repair

[grumpybeard]

Hi,

On PC start get boot error and can go into grub repair.

Can fix according to guide in video. Note that when I first type SET it lists a different a partition set as the prefix (hd0,gpt3 iirc), buit only setting hd0,gpt2 gets me back into a working grub and into Ubuntu. So perhaps the set to hd0,gpt2 is not sticking? or needs rebuilt?

https://www.youtube.com/watch?v=OJTGpvZO8Oc&t=308s

Which then starts up grub menu and I can select Ubunto.

However on every restart the same boot fail happens, so I have to go through the grub repair steps again as per Youtube vid.

I installed then ran boot-repair, with out put posted here:

http://paste.ubuntu.com/p/BwXtKjwk4w/



Most grateful for help as I need to complete a Uni assignment in Ubunto in a few days. Thanks!!!

[grumpybeard]

Looking at the pastebin from boot-repair, it shows it's looking for grub on gpt3, but it should be lookming on gpt2 (which I set after following instructions from youtube video and which gets me back into grub and Ubuntu)

Grateful for help on how I can change from gpt3 to gpt2 and make it stick, thanks!

Grub2 (v2.00) is installed in the MBR of /dev/sda and looks at sector
275620360 of the same hard drive for core.img. core.img is at this
location and looks for (,gpt3)/boot/grub. It also embeds following
components:

[grumpybeard]

below is what I do to fix on boot after grub goes into rescue shell. So how to make hd0,gpt2 stick?

grub rescue> set prefix=(hd0,gpt2)/boot/grub
grub rescue> insmod normal
grub rescue> normal

[oldfred]

Issue really is that with gpt grub needs a bios_grub partition to correctly install.
See line 1273 in report.

Shrink either partition by 2 or 3MB and create a new 1 or 2MB unformatted partition with the bios_grub flag.
Then do a full reinstall of grub to gpt's protective MBR (not just the update-grub).

[jeremy31]

Was there ever a third partition on /dev/sda

[grumpybeard]

@jeremy31 - you'd make a good detective! Yes there was. I was originally doing my machine learning/python stuff via a VM hosted in windows 10. Today I decided Im convinced enough with my Ubuntu full dedicated install that I didnt need my Linux VMs any more so blew that partition away. I really didnt think that blowing this partition away, which was only ever used in Windows, would cause this trouble. My next challenge is how to re-allocate the now spare ~120Gb to my current Linux partition. I believe I can do this with gparted but not when I am running Linux, so probs with a Live USB version of Ubunto or gparted iso? Anyway, thanks very much for checking in on this thread and your willingness to help, much appreciated.

@oldfred - following your guidance, all sorted, thank-you so so much. Tested with a restart and all good, grub showing each time now. You are a :KS , have a great day