Hi David,
many thanks for the link !
I have done a factory reset (multiple times), without luck.
I have also use the
testdisk utility to fix FAT partitions on SDCARD, which worked once, and after a new plugin/plugout on windows, same thing, partition is not readable anymore.
I will try a new clean SD card with your factory image.
I might think it is a hardware problem related to the USB interface...
Might take it back to the store if the original image doesn't solve the problem.
I will post if I find anything interesting.
Regis