Initial Callibration Failed on Toolhead 1 - am stuck

Excitedly unboxed my U1 this evening - put it all together and powered it up. Going through the initial set up

1. starts out in Mandarin - just had to guess which buttons to select

2. Got to the point where I could choose English and moved on fine, conntect to network fine, bound with the Snapmaker app fine

But!

When it started its initial callibration, I get the error saying toolhead 1 not docked. I checked it's positioning, matches in the installation and trouble shooting guides perfectly (as I see it) and the light comes on in all 4 toolheads so the USB C is connected to the toolheads as well.

I'm stuck, no clue what to do - can't even get to the spot to update the firmware.

Now the USB port on toolhead 3 was not in alignment with the box's hole for the USB C cable to push through to receive the cable. I pulled that into place (heard a click as it unbound from the plastic retaining it in a bad spot (so not great QA in manufacturing for starters), but once alighend the USB C cable inserted easily and was retained easily by the screws.

That was the only unusual thing I noticed on assembly. I wrote support, but it's the weekend in China now so i probably won't hear anything for a couple more days, but though I'd ask here if anyone has any tips/tricks to try for self help. I'm assuming the PCB board on the toolhead is malfunctioning or the mainboard is from the trouble shooting guide, but I've never worked with a Snapmaker product before so...................

Thanks for listiening all!