[///Mposter]

One last thing I didn't hear you mention. Did you ever start the car and put it in reverse or drive?
The EHB has intervened when I have been reversing and kept the door ajar. The vehicle rolled a foot and then the parking brake came on, then a screen warning.
Maybe you can get the brakes to reset by moving the vehicle first. Then try to get it to wind the EHB motor by the brake button, or if still inactive, then by leaving the door ajar while reversing. Maybe when both sides have equal rotation of the EHB motor, the error will go away.