Rx570 armor 4gb hiveos freeze or black screen


So i have 6 rx570 armor oc 4gb’s (Micron). I never really got them to work, bought them in 2017.

I recently decided to play around with these cards.

So i first flashed one back to stock. After a lot of tinkering i got it to work. it’s now hashing at 21mh/s on stock settings. Im actually glad i got it working stable.

Problem now is that i flashed back and added a second card. It works for around 30 seconds, than the second card stops working, than 20 seconds later the first card also stops and hiveos freezes (the command line of hiveos is visible but frozen + hiveos indicates the miner is offline).

So here i tried different rizers, different cables, check the bios label and rom, which seem to be goods altho vague ( Device Id is 1002 67DF - 1462 341A ).
S/N = 602-V341-250B1706001446. (V341 <> 341A , is it correct?)

Don’t know how to proceed.

All i can think off is that i need a micron specific rom to make it work, but cant find that. But than again, a single card works well.