Sounds very similar to what happens if you unplug a mounted USB hard drive from a running Linux without 'ejecting' it first. My understanding is that the kerne

Sounds very similar to what happens if you unplug a mounted USB hard drive from a running Linux without 'ejecting' it first. My understanding is that the kernel labels the device (recognised through its UUID) as 'read only' thereafter. And it is the whole device (i.e. /dev/sdb or whatever) that is labelled. Your symptoms just struck me as very similar. I can't offer any way forward alas.