After about a week of testing and setting up my new Jolla C I had to repartition my SD-Card that had one partition f2fs and one SWAP to ext4 and swap. I did so using parted from openrepos and creating a new partition table on said card. The card mounted fine on Jolla C as did the SWAP partition. After a while I decided to reboot the phone and since then it has not turned back on. No vibration, nothing.

I fear that somehow the NAND could be affected by partition table writing? Is there a way to connect NAND to a PC and check if everything is okay, or do I have to send in the device?

Connecting the Phone to PC shows QHSUSB__BULK in device manager - maybe this is a starting point towards flashing the device or repairing something.

Overview:

1: Tinker with partition tables on sdcard presumably - as that did work - mounted fine as swap and ext4
2: attempt reboot
3: stay dead
4: take out SIM and sdcard
5: attempt boot - stay dead
6: attempt recovery (vol-up + power) / fastboot (vol-down + USB) - stay dead
7: connect to PC - QHSUSB__BULK in device manager
8: open ticket at ZENDESK

Has anyone got a clue?

[EDIT]

9: get help from the inner circle
10: be educated QHSUSB__BULK mode basically exports the emmc via USB

[EDIT] (QHSUSB__BULK will either say Qualcomm 9008 (service port) or Qualcomm 9006 (emmc mode) the one we need)

11: expected behaviour on linux: show emmc partitions and list device on /dev/whatever
12: actual behaviour lsusb lists device as connected to one USB bus but does not list as any device to the system
13: conclusion - send in the device - as even with the by now provided original partition table, there seems to be no way to write them back to my Jolla C
14: sob and tremble uncontrollably
15: buy iPhone - jk

You may keep the pieces

I will decorate my trophy collection with this new brick! But I'd much prefer to let it age well before that

No worries. As far as I know you didn't bought a phone but part of a program.

Hou...tricky one...
Send it to jolla and tell them to fix it since it broke on first start up and request a new...

Just for the record, you did not mention trying to get into recovery menu.
You sure tried and it did not work, correct?

I had opened a ticket earlier and will await their answer.

Hope they can help me out.

I did try recovery and fastboot (voldown + usb)

Nothing works, the device stays black. Only thing is upon connecting to USB said device pops up in device manager indicating something is severely wrong.

Good to read you take it like a man

Me taking it this way is nothing compared to the poor folks longing for one and seeing me waste mine just like this.

Don't behead me!

At least you documented what not to do.
Can be helpfull indeed.

You did not mention if you tried rebooting without the offending SD card.