OK… I have some news here, problably bad ones…
lets first get back to what we wrote earlier in PM, thought its also good to share that info in case other people find it interesting or helpful. I compared the linux boot logs of my faulty Switch and a good Switch and indeed there are some differences, especially the line “Failed to set up IOMMU for device 57000000.gpu…” that pops up multiple times.
Here to compare, the BAD one:
And the GOOD one:
Additionally, before pulling anything off, I took out the board one more time to check some components using @Calvin 's diagrams (HUGE thanks for those, they are very helpful!!! 
) and I found loads of shorts to ground on the back side of the CPU (or GPU? that nVidia thingy… I think the one you call SoC 
), RAM and other places. Look at this image, I marked them all BLUE (ignore the red squares):
- I tried to measure as many as possible, but I might have missed a few, so there might even be more places.
- my multimeter beeps but shows a resistance of 7 Ohm at all those places with the short (the ground side shows 0).
- I also found shorts on some components the top side of the CPU board, where few little resistors/capacitors are around the main chip.
Also, on the following photo (back of CPU), I am not sure what those (blue circled) parts are that have these two additional solder spots on the sides of their “body”, which are shorted to ground too (it’s probably normal, but I am not sure). However some of the solder there looks as if it has been melted before, maybe the previous owner put it in the oven or something ^^
I also measured voltage to ground on this side of ther capacitor here as you suggested, and there is no reaction:
So you think this IC could still be the problem, or after all the other measurements would it be more likely the CPU/RAM itself, you think?
Phew!! 
