Hi, I had the same issue with an ssd, according to sandisk support , write protected mode is done by the storage firmware when it traces problem in the storage.
To save the user data , the drive is going to a locked mode.
Since SanDisk does not provide for most storage e.g sdcard ssd a firnware update or reconfigure tool you can say r.i.p to the storage.
Other option is to backup and do llf.
Hope this helps.
