I think I've bricked my H10 but I'm not sure and have no idea what to do about it. I was only given it yesterday too

During a firmware upgrade, something went wrong. Now I have a fully functional 6G USB mass storage device that does nothing else.
Turning it on immediately yields "USB Connected" regardless of whether a cable is plugged in. Plugging a cable in allows you to use it as a USB hard drive. Unplugging it produces the "Safe to disconnect" message. It can't be turned off using the power button, only by removing the battery.
Is it knacked ? Can it be fixed ? Is there a way to boot it properly ? I'd ideally like to run rockbox on it.
Any advice greatly appreciated.
TIA,
Veg