More often than not now I find that my K11 stalls at USB IN when I switch it on. The only way to power it off again is to unplug the power supply. Sometimes when powered up a second time it can be used as normal, sometimes it can't. 

At this stage I have tried every USB port on my PC and also tried a variety of different USB cables, so I can't see those as the source of the problem.

Mostly I have to enter the backup mode, revert to the original 1.05 firmware, then flash it back to the newer 1.22. This is a long way from ideal and I'm considering a warranty return. Is there anything else I should try first?