The SBCs are simple enough to install from scratch that it's probably not worth the trouble of upgrading. I just setup twelve of them yesterday in assembly line fashion. I suggest:
1) Remove the existing Micro SDHC card and replace with one loaded with the current Debian Bookworm armhf version.
The current V20 documentation indicates "Raspberry Pi 5 with 4 or 8GB RAM", but my personal experience is that Raspberry PI 4 units still work perfectly well with the current software. While I agree with the 3CX 4GB RAM specification, I also know the 2GB versions will work in a pinch and I think springing for the 8GB RAM version is money wasted.
2) Update Debian Bookworm to current revision with:
sudo apt update
sudo apt full-upgrade
sudo reboot
3) Then load the new V20 SBC software from the guide and place it into service.
Replacing - rather than reloading - the existing Micro SDHC card yields at last two benefits:
1) Flash memory cards have a finite number of write operations. Linux writes logs almost continuously and so it's possible the existing flash card might be approaching it's limit and should be replaced anyway.
2) Retaining the original flash card gives you a fallback option if there are problems.
In my opinion, for the $10 max that these cards cost, the above benefits make outright replacement worthwhile.
Ken Morley
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