I have just upgraded a Pi 4 from Bullseye to Bookworm. The OS seems to be running OK, but I am seeing a vanilla Debian desktop after logging in instead of the usual Pi desktop.
Maybe your experience justifies the caution expressed by Raspberry Pi when they announced the availability of RasPiOS Bookworm -
Bookworm — the new version of Raspberry Pi OS - https://www.raspberrypi.com/news/bookwo ... rry-pi-os/
We have always said that for a major version upgrade, you should re-image your SD card and start again with a clean image. In the past, we have suggested procedures for updating an existing image to the new version, but always with the caveat that we do not recommend it, and you do this at your own risk.
This time, because the changes to the underlying architecture are so significant, we are not suggesting any procedure for upgrading a Bullseye image to Bookworm; any attempt to do this will almost certainly end up with a non-booting desktop and data loss.
Statistics: Posted by B.Goode — Mon Dec 29, 2025 4:49 pm