Aileron and rudder reversed?

I own a Radiomaster TX8 and a Jumper T8SG v2, both running the same firmware.
The Jumper acts normal, I have to reverse both rudder and aileron for DSMX, trim works a intended.
On the Radiomaster, reversing those channel is not needed, but instead the trims are reversed.

Have I missed a setting in Deviationtx, or can this be fixed by simply changing the wiring of those 2 channels on the gimbal-plugs?

Sounds to me like those two channels have the gimbal pots backwards. Switching the wiring should work.

I wonder if all TX8's are like that.

So, it would work correctly, if I simply swap the plus and ground cable on the hall sensors?

Nope, that has just killed my TX, bummer

ouch. I mentioned gimbal pots as the TX8 looks like a T8SG clone with the LCD screen. Might be able to fix with new hall sensors and maybe power regulator(s).