Curious case of read-only flash drive

[MR ZenWiz]

I have a Toshiba 64GB USB3 flash drive that was working perfectly
until a couple of days ago.  I had reformatted it to NTFS because I
needed to transport files >2GB between my Xubuntu machines and Win7
machines, and I thought that was the only way.

At one point, I may have removed it from a Windows machine before the
safe to remove process had completed, even though it /said/ it was
safe to remove.

Since then, the drive claims it is read-only and I have yet to find a
way to undo that and make it usable again.

I have checked in the Ubuntu how-tos and in Google, and absolutely
nothing I have found so far actually works.  I can't write to it (or
delete what's on it), I can't format it - nothing.

I can read it just fine - saved everything for just that purpose.

I have not tried to follow the fractured English on the few Russian
sites that say how to find the drive's driver's maker and use that to
reset the flag - I'm hoping it's not that desperate an effort.  I'm
also trying not to void the warranty....

Is there a method that works, preferably from X/Ubuntu/Linux?

Thanks.
MR