VERY IMPORTANT: When charging do NOT power the phone on. Leave the phone powered off and simply plug the wall charger in. It will boot into Charge-only mode instead and give the battery a full saturation charge to 100%. This will take about 3 hours.
If you are stuck in a boot-loop and can't power off the phone, there are ways to recover and get to Charge-only mode by tricking the phone into a power-off through the Boot Mode Selection Menu. Let me know and I'll post instructions.
Can you post the instructions for tricking the phone into a power-off? Thanks!