I'm not sure if others have had exactly the same problem but this has happened a couple of times now with mine. I suspect that not using for varying periods perhaps corrupts some sort of EEPROM and/or whatever media the os is stored on. In any case, the solution seems to be to charge the unit for a couple of days ( even though it appears foobared ) and then attach the usb cable to a computer. Turn on the OP1 while holding the com button ( second down from the top rhs ) and you should then find the OP1 entering a bios screen. From here you can select an option to flash the firmware. You can download the latest firmware from the TE website and follow the instructions on the OP1 screen to do the firmware upgrade. I'm pretty sure this second time with mine I already had the latest firmware so it isn't a matter of just upgrading the os, it's reflashing/formatting/writing it completely. There was a useful Redit thread about this too, as mentioned by Justin above. It's a pretty nerve wracking experience having...