Glo HD Reader doesn't boot after repair, shows up as "SE Blank MEGREZ"

[felurx]

Hey there,

I recently replaced the broken microUSB port on my Kobo Glo HD with a USB-C port. The fine soldering was a bit of a pain, but I got the port to work for charging and connecting to my computer! ...Unfortunately, it doesn't boot anymore

To be more precise: When I connect it to a computer via USB or when I press the power button, the red LED lights up, and with lsusb I can see a USB device labelled "SE Blank MEGREZ" (15a2:0063). Other than that, nothing much seems to happen. The screen stays on the "Turned off" image, and there isn't even any output on the serial ports.
(I tried hooking up a pocket oscilloscope to the TX pins. Apparently, the one on the upper right should output a boot log: https://wordpress.panaceas.org/wp/in...acking-part-1/)
For what it's worth, I also poked random test points and didn't see any signal on those either.

Someone else had a similiar problem with their Kindle Touch 2 here: https://www.mobileread.com/forums/sh...d.php?t=326181
Since I have had the Kobo just lying around in a shelf for a long while before doing the repair/mod (and stupidly didn't test it before the mod), I thought that it might be a problem with the battery controller locking out after after a overdischarge as described in the thread. But I tried monitoring the battery voltage while having a USB cable connected, but nope, it did charge and eventually reached 4.2V. So that seems to rule out that explanation.

The SD card works fine when connected to my PC, so I think it isn't a problem with that. Just in case something got corrupted, I asked for an image and wrote that to the SD using dd, but that didn't make a difference either.


I don't really know what to try from here. I think the most likely explanation is that I fried something while doing the repair, but I thought I'd just see if someone here has any ideas for how to revive my old friend before I give up on it.