3) If you know what you are doing, it is usually possible to grab the appropriate "firmware" files from a current version of RaspiOS and "Frankenstein" them into your existing system and if you're lucky, have it work. This may or may not be something you care to look into.
For, say, 2B to 3B I'd agree. For 4B to 5, not so much. Too much changed with the introduction of the RP1 "southbridge" which an old OS won't have the drivers for. No drivers likely means no GPIO, no USB, no ethernet, etc. Newer firmware (boot files) won't help with that as it's an OS/kernel issue.
Though, to be absolutely clear, I haven't tested it - you might be lucky and I might be wrong.
The next not recommended and not supported option would be to try an in place upgrade between major OS releases on the 4B. Some folks claim it works but, again, I've not tried it. Take a backup first. No, I can't advise on how to do such an upgrade.
Statistics: Posted by thagrol — Tue Mar 25, 2025 1:38 pm