Black screens after soft reset (2018 MX 75D). Need help!

[Thebundok]

2018 Model X 75D. Warranty expired literally 2 days ago. I'm fuming because of the possible implications.

Supposed to go on a ski/cabin trip tomorrow with kids. Last drive of the day today parked the car with 25% battery. Home charger was having problems starting the charge. I did a soft reset (hold both scroll wheels) and the car rebooted but both the Instrument Cluster/HUD and Touchscreen are black.

Instrument cluster backlight comes on, but no Tesla logo and no displays. Have tried driving it around to see if that would trigger something, even did another soft reset while driving. No changes. App can see the car and get updated info, but can not trigger any commands (open doors, climate etc.). Oddly enough, the car would accept a charge after the "failed" reset.

I let the car charge back up to 90%, tried another reset, and still no change. The car is drivable, but without any instruments extremely unadvisable (especially through snowy mountain passes).

I've disconnected any USB attachments before resetting, no change. I can't do a power off reset as I don't have access to the touch screen. I've read that I can disconnect the 12V in the frunk to accomplish the same thing, but accounts I've read seem varied. I'd have to go in manually as the app won't open the frunk.

Can anyone confirm that disconnecting the 12V will perform the same function as a power-cycle reset Do I disconnect both negative and positive (in that order)? Do I have to leave it off for a specific period of time?

Any other tips? I tried calling Tesla Roadside but they're closed until tomorrow and no guarantee they'd be open tomorrow. It's Sunday here now (Norway) and tomorrow is a holiday.

Thanks in advance. I'd hate to cancel this trip last minute.

 

[Thebundok]

UPDATE: Disconnected the battery following a video tutorial on battery replacement. Car did a power-cycle and the instrument cluster came up. It also displayed a warning that the "Touchscreen [was] unresponsive]" and to perform a reset (with the scroll wheels). I did another reset and back to square one. No touch-screen, no instrument panel. So I disconnected the 12V again and now we're at least to a spot where the car is safely-(ish) drivable.

Took the car for a test-drive. Immediately noticed that the system was reset from km/h to mph. Scroll menu response time is extremely sluggish (e.g. multiple scrolls just to change the fan speed). But the kicker is that, because the battery was disconnected the Falcon Wing Doors need to be recalibrated... via the touch-screen. So now they won't open at all. So that pretty much seals is that tomorrow's trip isn't happening.

Not sure what all this means in terms of what's wrong. Worst case, whole MCU needs replacing? Best case, it's a loose cable? Next stop Tesla Service, I suppose. Maybe they'll be kind and extend my warranty by 3 days? >.<

 

[Miamipoker]

so what was the issue?