Libra 2 Kobo Libra 2 brick LED flashing does not turn on

[czullo1]

Hi, my Kobo Libra 2 stopped turning on, so I took apart the case and checked the battery with a multimeter, and it has a good voltage of 3.7V. When I plug in the charger, the device charges without any problems to 4.125V. Then I removed the old microSD card and thoroughly cleaned the memory card slot with isopropyl alcohol and a brush. Thanks to @DNSB, I downloaded the firmware versions compatible with my motherboard and recorded them on a new microSD card, but the symptoms are the same as with the old memory card, which is read without any problems by the PC when connected via an adapter. I tried all the combinations found here on the forum (holding the power button for 15, 30, 60 seconds, holding the page change button + power button for 15, 30 seconds), but the only thing I managed to achieve was that when I connected the reader to the computer with a USB-C cable, the white LED on the reader lit up and started flashing, and after a few seconds it went out, but the device did not turn on. When the reader is connected to the computer and I press the combination of keys (page up or page down + power) and hold them for 15 seconds, I hear the sound of a new device being found in Windows, and after a second of disconnecting the device, sometimes even the screen backlight turns on, but the screen still displays the book that was being read before the device became a brick, and I cannot click anything on the screen. After a few minutes, the scree lights turns off and the contents of the reader are recognized by the computer, but the screen still displays the contents of the book and nothing can be clicked on the screen.

Any ideas what could i try next?