cgsecurity.org

well... yes, I also tried switching the write-protect switch ;-)
The electronic is fine. The cards have been used on a device (POS) that somehow locks them for writing on any other device (the device writes them and can modify the files, the files are visible and readable on a computer) but ...

I seem to have exactly the same situation on a few SD cards. Did you ever found a solution?

I have a few SD cards that appears to be write protected with some advanced method and I do not manage to write on it nor reformat it.
I have tried with all the usual methods I could find, but nothing works. I post here the testdisk log of
Analyse > Quick Search > Deeper Search > Delete (clear MBR ...