Line6 took away 2-3 hours playing time with new Relay G10 firmware. The new fw. does not allow the battery voltage above 4.0V
Normally the li-ion battery maximum voltage is 4.2V.
I supposed they got a wrong battery contingent from China, which overheated during normal charging. Sold and got panic.
The old firmware has gone...
Fortunately I can charge my piggyback (1200mAh) battery from outside to 4,2V. >> 12 hours playing time.
This story is a typical Line6 story....