Raspbery Pi OS Lite stuck on kernel 6.1

I have a Pi Zero W that was running running a Debian 11 version of Rapsberry PIOS Lite. It was originally running Debian 10 and was successfully updated to 11 by an in-place update. The Bullseye update fine and with a few mods to minimise SDcard writes has been running for years.

A while back I upgraded it in in-place to Bookworm and it went OK. I think there were some strange network rules such that the Wifi is not managed by NetworkManager but it works fine. This Pi runs headless and is used as an SSH gateway from the wonderful internet to my network.

OK, I did an in-place upgrade which they say you should not do but it worked and the Pi is 100% fine. And I did an in-place upgrade again which worked. So that's 10->11->12

Except... I've noticed that the kernel is stuck on 6.1.x from 2023 and whilst there are updates for the components when I run the regular "sudo apt update / sudo apt upgrade" the kernel doesn't get touched. Looking on the PiOS website it's says Pi OS lite 32bit is on kernel 6.6.

So my question is whether there is some way with apt update/upgrade to get the kernel updated? Or I am facing (what I expect to the case) that I need to do a clean install of the latest image and re-apply my SDcard wear reducing mods?

Ideas?

Debian does officially support that, provided you do not go up more than one major version step at a time.

The kernel is just another package, with a name like “linux-image-«version»-«arch»”. Look for packages with that form of name, and try explicitly installing the version you want. But yeah, I thought this should be automatic.

Thanks for the suggestions. Spending a while looking about the system showed there was no linux-image-xxxx package installed. I don't know how that actually happened but it would explain why the kernel was not being updated. The kernel would be the files from bullseye I'm assuming. I had a few half-hearted attempts to try to install the linux-image-6.1.xx package that the currently installed kernel came from but I got errors each time I tried.

So... I took the MS way out and blitzed it with the latest image and installed on a new card. A bit of headless setup fun and then checking in an A+ with a serial console and a Wifi dongle meant I could confirm everything was working. SDcard into the Pi Zero, booted up and auto connected to the Wifi. Followed by apt update/upgrade, copy some files from the old card, install fail2ban, make the wear reducing changes and we're back in business.

I've kept the old card so I may try seeing I can can fix the borked install and get it to update. I feel I'd understand things better that way. I don't know if this was the result of doing an in-place update from bullseye to bookworm.

Thanks for the comments.

And I've had to fix the systemd issues so fail2ban works and enable nftable.service so nft rules get loaded on boot. No doubt there'll be more.

Systemd: the gift that keeps on giving.

My in place upgrade installed the 6.6 kernel, that was on a 64 bit install, but 32 bit should do the same.

---druck

Yes, but you should then read the "upgrade" chapter in the debian release notes for the new version - sometimes there are manual steps required (I remember "pick a kernel package and install it", but I am not sure for which version that was). Of course, debian will not list raspbian-specific topics, so these need to be considered additionally.

On i386/x64, I have done lots of in-place upgrades, in one case starting at Debian 3.0, and all worked fine - I don't know why is is recommended to do a fresh install for new raspberry pi os versions.

cu Michael