Aura HD aura HD frozen after running out of battery, all usual reset methods not working

[nihilazo]

Hi,
I was reading a book in koreader on my kobo aura HD when it ran completely out of battery and froze up - I can't turn pages any more and the device is totally frozen.
I've tried charging it (from both my PC and a USB power socket), holding the power button for up to a minute, resetting using the reset switch, and pressing the light button while holding the power button (all tried while both plugged in and not) and none of these have managed to unfreeze my kobo. is there any other method to try and unfreeze a kobo in this state?

Thanks


EDIT: it seems the USB port on my kobo is just a bit dodgy and it wasn't charging. I can't delete the thread, so I'm just leaving this edit here.