Exactly the way forward from here! It's both good and bad that 48 won't dump properly. It may be an indication of physical damage or there is something very wrong written to it. If it's a severe corruption it might not be possible to even effectively overwrite it and accordingly it may not be possible to remove the corruption with 'xrgn'. If that happens then the only other option that i know will be to attempt to erase region 48 complete with 'ergn'. Doing so successfully should allow it to be seen in Disk Management and then require a reformat with [Only registered and activated users can see links. ]. If neither xrgn or ergn work then it would indicate to me that the flash is damaged rather then just corrupted.

You appear to know precisely what you're doing .... so good luck Mate.