I need help troubleshooting my Kobo Libra Colour e-reader. It's completely stuck on the "Please recharge" screen and won't respond, even after trying multiple fixes including a brand-new battery. The white LED charging indicator lights up, but the screen never changes.

What I've Tried So Far:

• Multiple wall chargers (5V/2A) and USB-C cables (known good ones)
• Charging undisturbed for 24-48+ hours on both old and new batteries
• Soft reset: Power button held 20-30 seconds (LED blinks)
• Manual/factory reset: Page turn button + power button held 30 seconds while charging
• Battery cycling (unplug/replug 20+ times while charger connected)
• Inspected USB-C port (clean, no visible damage)
• Verified new battery connector fully seated, correct model/compatible replacement

Current Symptoms (Same with Both Batteries):

• White LED illuminates when charging
• Screen stays frozen on "Please recharge" - no progress, no boot
• Not recognized by PC (no drive mount)
• No response to any button combinations

Theory: Suspect charging controller, display driver, motherboard, or firmware brick. Battery swap ruled out power issue since symptoms identical.

Questions:

1. Anyone fixed this exact "dead screen but LED works" issue on Libra Colour?
2. Could it be the battery management system (BMS) needs special reset?
3. Mainboard replacement viable?
4. JTAG/short-to-reboot possible, or is it bricked?
5. Kobo support dead-end?