On Thu, 24 Oct 2019 15:31:06 +0000, BIG Umberto wrote:

> I have an pi3 working with a raspbian stretch.
> I must migrate the full system to a pi4b.
> I have copied the sd of pi3 (both the partitions) into 2 file with 'dd'
> in hd of my pc (debian).
> After, I have create the 2 partitions into a new sd card (same model)
> and copied the 2 image-files created before. Pi4 not work!
> Must I install a new image from repo (raspiann buster) and re-install,
> recompile all my software and reconfigure all?

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.

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