I have a similar problem. The unit works fine as long at it is connected to a charging cord. When i disconnect it the unit locks up and will not function. The battery is showing as fully charged. The unit functions disconnected from power in the radio mode. However payday loansi can only turn the unit on using a power cord. It will not turn on without being connected to some form of external power. I have tried to reset the unit 20-30 times and always the same results.
Try re-installing the firmware manually. If this doesn’t help, it’s time for a new player. You can find the latest firmware here.
There are 2 firmware versions. Make sure you download and install the correct one for your player.