debian+phosh running on PinePhone

[LazLong]

Yeah,  normally I have no problem 'just flashing' to an sd card, but on occasion when it does not boot,
I have found that a good zero wipe of the sd card, then a re-flash and it does work.

I second that.  A good wipe seems to often clear up problems with a bad flash.  I have begun routinely
'cleaning' the uSD before flashing a new image to it.  Of course, we know that these cards only have so
many 'writes' to them so this does add wear and tear and probably reduces the useful life of the media
to some degree.  However, doing the prophylactic wipe seems to avoid frustration and wasted time.
No doubt this is anecdotal so take it for what its worth.