Hi, I did what tshering suggested above:
- Download the latest firmware for your device here.
- Connect your device to a computer.
- Copy the contents of the zip file to the .kobo folder on your device.
- Disconnect from PC.
- Restart device into KSM.
- KSM will have new menu item handle update. Use that to (re)install Kobo firmware.
If all goes well you'll end up with a working device, but without KSM. You can reinstall KSM after verifying that all works well in the stock firmware.
Good luck!