Atem TVS 4K Downgrade to 7.4 does not work

With Firmware 7.51 the new Atem TV Studio 4K does not work with GPIO Boxes anymore for Tally.
So I have to downgrade back to 7.4.
After deinstall 7.5.1 and install 7.4 the Atem Setup does not recognize the unit anymore. Atem Control works with no problems but the unit does not downgrade the software. What can I do?
Thanks Guys

I noticed some weirdness with the 7.5 patch as well. My 1 ME PS 4K didn’t seem to do a noticeable firmware update. Even though the setup “confirmed” it was 7.5
I tried to downgrade back to 7.4 because it seemed a bit odd and same deal, no noticeable firmware push. Even though my 1ME panel did do a update.