Upgrade Debian from buster to bullseye
I had two Raspberry Pi systems running Raspbian and they were failing to find updates for newer packages. As Debian stable was upgraded too, moving from buster to bullseye the packages failed to get the newer ones. Warning Beware as this procedure might upgrade the system but might no render a bootable Raspberry Pi A way to fix it is, to first, change references, if any, to the old codename version by running: ...