Ubuntu 25.10 upgrade issues

[Brian Alex]

I finally got Ubuntu 25.10 installed (upgrade from 25.04) but it won't boot. There was a notice during install that "Writing GRUB to boot failed"

I found the following command to fix that; "grub-install --target=x86_64-efi --directory+boot/efi --bootable-id=ubuntu --recheck".

Seemed to go well until it returned "Error: failed to get canonical path of 'boot/efi' "

So close. Is there another approach or is there an easy way to just install 25.10 over 25.04. It is a dual-boot with Mint 22.3 (primary every day system). I did make a bootable 25.10 and tried to boot from it but couldn't get past "try or install ubuntu". I get the Kernel Panic "Can't boot fs to unknown block" message. Thanks -BA I'm way over my head but am determined to figure this out. Since this is just a back-up system, I could just wait until the next long term release (July?).

ps I used TS to return it to 25.04

 

[Condobloke]

Boot Repair is the tool to use

if 25.10 will open the Live version, then hopefully boot repair is in the menu, or the software centre which is already in 25.10 (hopefully)

If all else fails: https://thelinuxcode.com/how-to-fix-ubuntu-boot-problems-a-practical-realworld-guide/

 

[wizardfromoz]

Two Brians to address here.

Brian @Condobloke that's 25.10 on both counts, not 25.1.

and

@Brian Alex

I could just wait until the next long term release (July?).

April, actually, for 26.04 'Resolute Raccoon", and LTS (long term support) version. Might be best waiting for that.

BTW it should be Ubuntu 25.10 in the Title, not LInux 25.10.

I will/have change/d that, and moved this to our Ubuntu subforum.

Wizard

 

[Brickwizard]

I did make a bootable 25.10 and tried to boot from it but couldn't get past "try or install ubuntu". I get the Kernel Panic "Can't boot fs to unknown block"

That looks like it may be either a corrupt download or a bad burn to the USB . Did you c heck the SHA sum?

now back to the grub error, do you get the grub screen when you boot Mint? if yes is Ubuntu showing on the list ?? if no then try from Mint terminal
sudo update-grub [then re-boot] is Ubuntu on t he grub screen now?

 

[kc1di]

As at @Condobloke has said you can try boot- repair but I have found that it is not the greatest lately. So may not work.
At this point since this is a new install I would try the a new fresh install. Not an update. Back up of computer your important stuff and simply install it from live usb. Or as Chris has said just wait for the next LTS release in April. In any event good luck.

 

[Brian Alex]

Thanks for the thoughtful replies. I've been considering them all and decided that the prudent decision at this point is to just wait for the next LTS version and learn how to get that installed over the 25.04. I've spent too many hours on this already but at least I have learned a few things. Thanks! -BA

For the record, the program I used to flash the USB did "Verify" so I assume (?) that means checking integrity. I used a known good USB drive. Yes, Ubuntu is visible on GRUB when booting with the choice of Mint or Ubuntu with various alternate options. I used recovery and tried each option; repair broken packages, boot repair, Etc. It was from the "Root" option that I attempted the boot repair command listed in the OP. Anyway, Mint is running great guns and I'm very pleased with the improvement over that other system I had been using for 20 years. -BA

 

[KGIII]

and learn how to get that installed

You can (almost certainly) just use the in-place upgrade method offered by the system. In its default configuration, Ubuntu will tell you when upgrades are available. That can be every upgrade or just the LTS upgrades.

You'll get a notice and can follow the prompts.

Judging by the comments we see here (or at the official Ubuntu support services), doing the in-place upgrade is successful for the vast majority of people. When upgrades happen, there's no giant influx of users asking about it. So, there's that.

Me? I do in-place upgrades and only in-place upgrades (unless forced to do otherwise). I've been doing this for well over a decade. In my experience, the days of needing a clean install for upgrades are long over. It's just a 'non-problem' these days.

I will note that, for my Ubuntu stuff (I use Lubuntu, which is just Ubuntu with some different default packages), I only use the LTS versions. It's not that the interim releases bother me. Nor do I see upgrading to the interim releases as problematic. It's just that I prefer stability. I like a degree of 'sameness' with my operating system. I don't need to be cutting-edge and constantly changing my processes.

 

[Brian Alex]

Thanks KGlll. I'll try the in-place upgrade utility when the new Ubuntu version is released. Hopefully a better result that the 25.10 attempt. What a mess. Reminds me of Win-10 where I spent the entire holiday season trying to salvage my system and data (only partially successfully) after a horrible update a few years ago. Oh well.

Thanks -BA

 

[KGIII]

Reminds me of Win-10 where I spent the entire holiday season trying to salvage my system and data (only partially successfully) after a horrible update a few years ago.

The good news is that it's trivial to recover your data with Linux. Just load up a live USB version, mount the drive, and you're good to go.

This is slightly more complicated if you've encrypted the storage drive. In that case, you're pretty screwed if you've forgotten your decryption password. That is by design, of course. If it were easy to recover the data, it'd be easy for the bad guy to do the same thing. So, of course, you can't realistically recover that data.

 

[Brian Alex]

No encryption for me, yet.

I've tried twice to boot from a live Ubuntu 25.10 USB but both times I get "kernel panic. Failed to boot fs from unknown block".
Maybe I should try a Mint 22.3 USB since that is the system that contains all of my important stuff. I'll try it and report back.

Same result with Mint USB. There is a notice that flashes for maybe .3 seconds that says "failed to open ........" (can't finish reading) then Grub 2.12 with Mint and Ubuntu selections. "can't mount fs to unknown-block (0-0). So I need to figure out another form of back-up I guess.

 

[KGIII]

I've tried twice to boot from a live Ubuntu 25.10 USB but both times I get "kernel panic. Failed to boot fs from unknown block".

That looks like an improper 'burn'.

What are you using to write the .iso file to the USB?

 

[Brian Alex]

Thanks for the response. I used the built in utility ( right click the .iso, "create a bootable usb") and also Etcher with verification. I get a very quick warning "Failed to open efi/boot, file not found". So I guess that's the issue. Back to the drawing board. -BA

 

[Condobloke]

That perhaps leaves the usb stick.

The create bootable usb app etc has never been known to fail

 

[KGIII]

"Failed to open efi/boot, file not found"

That's a missing or corrupted boot loader, more likely than not. It could be a bad burn, corrupt .iso, bad USB, etc...

I don't normally suggest this, but I'd double check to make sure that 'secure boot' is disabled in the BIOS.

 

[Brian Alex]

Well, I don't know really how to use check-sum or whatever it's called but when I enter the figure provided by the download source into the bottom line and click verify, it says it is a bad download and try again.I did with the same result. So I give up. I'll wait until I have a real problem to trouble the good folks at Linux.org.


Oh, no secure boot.