Migration from pi3 to pi4

On Thu, 24 Oct 2019 15:31:06 +0000 (UTC), "BIG Umberto" declaimed the following:

The R-Pi 4 requires Raspbian Buster (the foundation actually released a Buster based Raspbian some two weeks before Debian itself released Buster

-- because they had no working OS available when the R-Pi 4 hardware came out). The R-Pi 4 required significant changes to the booting logic.

Or you can do an in-place upgrade on the pi3 and then move to pi4. Just replace 'stretch' with 'buster' in you /etc/apt/sources.list then 'apt update' and 'apt dist-upgrade. It will take a while.

The reason is that as the pi4 was developed, it had different architectural featues from previous versions, so the choice was - modify stretch to accomodate and then finish the work on buster. So they eliminated one step.

You also need to follow that with an rpi-update otherwise the image will not have the additional files needed to boot the 4B.

---druck

OK.

Yes. The boot partition of pi4 is much large respect the pi3.

Testing tomorrow for a hibrid mode: Boot of pi4 and second partition with files of pi3.

THANK.

As my setup had been through many migrations between generations of Pi's my boot partition wasn't big enough for the RPi 4B files, so I had expand it to 256MB.

You should be able put a Pi 4B Buster back in to a Pi 3B, as it contains files for both.

---druck