After some poking around it was sort of working - not entirely surprising since the timing for driving these displays is quite tricky sometimes.

Unfortunately that questionable soldering did turn out to be a problem on some pins - while I think I’m getting the hang of soldering these things now, I’d bent some pins and while I did try to straighten them, it just made more mess and lifted a couple of tracks.

The good news though is that I have enough of a board to try out some other ideas on, and I should be able to assemble one more board properly now I’ve learnt what to avoid!

The STM32F407ZET6 parts come packaged telling you to use a vacuum pen to remove them and they’re fragile - they aren’t kidding about this! I got a cheap vacuum pen from Amazon and from playing around a bit it should make it far easier to not bend pins. 

I’ll get there eventually! 

The last rework attempt - while not entirely successful - did work fairly well until I spotted the bent pins.