Iriver h340 battery too low to boot

[Thrillhouse]

I haven't used my h340 in a while, so I'm assuming the battery ran down pretty low.  It won't boot when I press play, so I tried hooking it up to my computer via usb (I have to charge this way as my ac jack is broken).

The initial splash screen comes up, I get a "Warning: Battery Low" message, and the player shuts off.

I also tried booting into the original firmware with the usb in.  I get to the Iriver splash screen, and the player stops and cuts off.  I'm 90% certain that I left usb charging on in the original firmware.

Does anyone have any ideas how to get my player running again?