You had it working on a previous version? Was the card in the Amiga or outside the amiga when you flashed 1.8.3.
Yes, the last version that was on it was 1.7.1 I believe.
I flashed it while still in the Amiga using the procedure described here.
But I should have updated the drivers first because after flashing it would display only garbage.
Anyway, after powering on the Amiga (4000D), I wait 2-5 secs and make a soft-reset, then I get a picture.
Seems like some timing issue to me.
Manfred