Do you run Ubuntu on a Raspberry Pi? If you do, there is a major boot change coming in Ubuntu 25.10 you will want to be aware of — but don’t worry, it’s for the better.
Canonical software engineer Dave Jones has laid out plans for ‘substantial’ rejig in how the distro boots on the Raspberry Pi, describing the current approaching to booting as ‘far from optimal’ — in fact, he calls it “Bad with a capital B”.
How come?
Well, because the current approach makes it a little too easy for end users to find their Raspberry Pi not booting after an update, be it due to power loss/interruption during an installation or just a dodgy update (since it happens).
For those who run Ubuntu on a Raspberry Pi as a home media server, a network-attached storage device, or some vision-spotting inferencing AI-doodah to catalog the birds in the backyard, the lack of a built-in fallback means if the system fails to boot, no dice.
Which is especially annoying if said Pi is running at a remote location.
Backup files exist, but they are are obtuse to find without arcane commands, and a little hard to work with since, weirdly, they are often broken! The only thing worse than no backup? Something pretending to be a backup.
This is why things are changing in the upcoming Ubuntu 25.10 release with “tryboot”, a new approach aiming to improve system recovery and reliability when running Ubuntu on Raspberry Pi hardware.
What does this change mean for me?
“We’ll be moving to a system that will “test” new boot assets and automatically fall back to a “known good” configuration in the event the test fails,” Jones explains. The goal is to bolster Ubuntu’s reliability and mitigate hassles caused by boot failures.
The new system will automatically fallback to a last known-working configuration if a boot attempt fails.
If you are an end-user who runs an Ubuntu desktop on a Raspberry Pi to use as a regular OS, this change should mean you always have a working desktop to boot into whenever you install updates, even if those updates fail.
If you use Ubuntu Server on a Raspberry Pi as a server, for IoT or other specific needs, this new approach should help avoid unexpected downtime and manual intervention if things go wrong.
Emphasis on the ‘should’ since, y’know, this is a change and changes need to be tested.
Testing ‘TryBoot’ on Ubuntu Pi Builds
To that end, anyone willing to help try the new ‘tryboot’ approach to booting Ubuntu on their Raspberry Pi can do so (but are asked to file bugs against the flash-kernel package, tagged with raspi-image).
To test, flash the latest Ubuntu 25.10 daily preinstalled IMG for Raspberry Pi to a good-quality SD card, boot it on a supported Pi device, and set it up as normal.
- https://cdimage.ubuntu.com/ubuntu/daily-preinstalled/current (desktop)
- https://cdimage.ubuntu.com/ubuntu-server/daily-preinstalled/current (server)
Then, add the following testing PPA (for now; this package will be available in the questing repos in the next week or two):
sudo add-apt-repository ppa:waveform/flash-kernel
Then, install the following new package from the PPA:
sudo apt install flash-kernel-piboot
The flash-kernel package will be updated during the process to “migrate the content of the boot partition (mounted under /boot/firmware) to the new layout”, per Jones’ blog post.
That layout:
- Currently booted “known good” boot assets >
/boot/firmware/current - Untested new boot assets (i.e., from updates) >
/boot/firmware/new - Previous “known good” boot assets >
/boot/firmware/old
Thinking that’ll take up a lot of space on your 32GB microSD card? It shouldn’t; to reduce the amount of space taken up by packages, the old/ folder is removed whenever new/ assets are written by the flash-kernel package.
If you run Ubuntu through something like PINN/NOOBs (which allows you to install and boot multiple OSes on the same drive on a Pi) you’ll be pleased to hear the team is working to ensure that this try-boot method works with it.
A double-boot drawback
There is a (slight) downside: double-boots, due to the way that processes involved in testing a boot and moving things where they need to go chain together, as Jones notes:
“Each time flash-kernel is run for whatever reason (new kernel, initramfs rebuild, etc.) the next boot will be a double boot. This will probably be a bit jarring to people at first (“why did I see the rainbow screen twice?!”), and also means that boot will take roughly twice as long (obviously).”
“However”, he adds, “I don’t see a way around this and, to be frank, it’s a small price to pay for the reliability that this mechanism should bring.”
Those who don’t want to go through the hassle of a double boot every so often will be able to avoid double boots by running sudo piboot-try --reboot. This new command will have other options, and a manage on how to use it.
In all, this is an exciting change that, though deeply technical, is beautifully simple in its aim: to allow those using Ubuntu 25.10 on a Raspberry Pi to not simply use it, but be able to rely on being able to use it thanks to this near-invisible safety net.
Want to learn more? Grab yourself a coffee and head over to Dave Jones’ full blog post write up to swot up on the how’s and why’s in – it’s a long, comprehensive and pun-laden read.