Hmm.  Seems this might be a good reason to back up externally.  Just did this evening in fact! And, thanks for the reminder!  I have this on an NVMe drive in an external case, and just put it in a Faraday-cage bag, folded it up and put it in another one.  (I had previously tested with my cell phone, and it rang in one but not in two.) Considering printing as well, although that takes a lot more storage space.