I recently purchased Pi Position with Raspberry Pi 3B+. I've imaged a 32GB card (2021updaterev2) and copied over the Pole Position roms. BTW: there were two roms already there which I copied over.
When I connected this to Pole Position, I wasn't able to see anything and it looked like there was a sync issue, but there was no game playing in the background.
When I tried to connect just the Raspberry Pi (no Pi Position board) to an LCD via HDMI and powered separately, I only get a rainbow screen.
I've reimaged the card twice, no changes. When I reimaged the card using RetroPie, that worked just fine.
What step did I miss here?