On Tue, Mar 6, 2018 at 3:01 AM, Jim Karlock <jjkarl...@gmail.com> wrote: > >> My initial attempt to google this was unsuccessful (most people point >> out the write protect tab, not my problem). > > > Bad switch on the write protect tab? (The tab operates a tiny switch.)
Nope. I can turn the switch to lock and it mounts the device read only very clearly. The behavior I observe is that it happily writes /dev/zero over the block device, but then when I read again, the old data is still present. > > thanks > JK > > > > At 01:25 AM 3/6/2018, you wrote: >> >> I started playing with my Pine 64+ quad-core ARM64 board again >> recently. I have a 16GB Samsung EVO microSD card I was using >> previously. I started out by zero'ing it: >> >> dd if=/dev/zero of=/dev/sdc bs=1M status=progress >> >> which seemed to finish fine. But when I remove and re-insert it, it >> still has data on it. Double-U Tee Eff? I have tried the same >> process on three different machines with different methods of >> connection (in an SD adapter in a USB-SD reader; in the SD adapter in >> a laptop SD slot (probably still USB internally); and directly in a >> microSD slot in a second laptop). >> >> I get no warning about being read only. The writes seem to occur >> successfully and fully complete. I sync before I remove the media, >> plug it back in and all the old data is still present. >> >> My initial attempt to google this was unsuccessful (most people point >> out the write protect tab, not my problem). >> >> Any similar experience, and/or clues for recovery? >> >> Thanks in advance. >> >> -- >> Russell Senior >> russ...@personaltelco.net >> _______________________________________________ >> PLUG mailing list >> PLUG@pdxlinux.org >> http://lists.pdxlinux.org/mailman/listinfo/plug > > _______________________________________________ > PLUG mailing list > PLUG@pdxlinux.org > http://lists.pdxlinux.org/mailman/listinfo/plug _______________________________________________ PLUG mailing list PLUG@pdxlinux.org http://lists.pdxlinux.org/mailman/listinfo/plug