Re: [gentoo-user] SD memory card not erasing, even with dd.

[Mark Knecht]

On Wed, Dec 29, 2021 at 12:15 PM Dale <rdalek1967@×××××.com> wrote:
>
> Mark Knecht wrote:
> > On Wed, Dec 29, 2021 at 10:14 AM Dale <rdalek1967@×××××.com> wrote:
> >> Mark Knecht wrote:
> >>> <SNIP>
> >>>> So while rare, it's not just me.  ;-)  I've had cards fail by just plain
> >>>> refusing not to mount at all, mounting read only and such.  I've never
> >>>> had one to fail like this tho.  I guess if this was some sort of
> >>>> sensitive files, I'd have to put it in a shredder or take a pair of
> >>>> scissors to it.  LOL
> >>>>
> >>>> I ordered 6 new cards as replacements.  They came in yesterday.  Like I
> >>>> said, I wouldn't trust that card even if it started working again.  So,
> >>>> off to the trash the weird card goes.  Now I just have to wonder why dd
> >>>> and such didn't report problems.  :/
> >>>>
> >>>> Thanks to all for the info.  Interesting.
> >>>>
> >>>> Dale
> >>>>
> >>>> :-)  :-)
> >>>>
> >>> Actually, it's possible that it failed this way by design. What if the
> >>> card recognized that it's in some sort of a wear out condition and
> >>> just shut off new writes? One might see it as a failure but a
> >>> different view is as a potential opportunity to retrieve data before
> >>> it's gone.
> >>>
> >>> You might want to check out this tool:
> >>>
> >>> https://github.com/BertoldVdb/sdtool
> >>>
> >>> which advertises that it can view, set and reset the write protection
> >>> status of an SD card. Can't hurt if you're committed to throwing the
> >>> device in the trash can anyway. (Well, it could possibly hose your
> >>> system if you use it incorrectly or if it has bugs, but that's true
> >>> about all software, right?) ;-)
> >>>
> >>> But at least you could view the status of the card.
> >>>
> >>> Cheers,
> >>> Mark
> >>>
> >>>
> >>
> >> I downloaded sdtool but I don't have the required devices in /dev to use
> >> it.  In the readme it says not to use /dev/sd* but to use /dev/mmcblk*.
> >> It seems my card reader doesn't connect in a way for those to be
> >> created.  Would have been nice just to see what it does tho.  I still
> >> wouldn't trust it of course but being curious . . . .
> >>
> >> By the way, the card is a Sandisk which has a fairly good reputation.
> >> It is possible that it failed in the best way it could.  On the positive
> >> side, it did fail in a way that the files could be recovered.  That's
> >> always a good thing.  It's certainly better than failing with no way to
> >> get the files.
> >>
> >> Dale
> > OK, sorry it's not easy. I suppose now that you are using some sort of
> > USB bridge for reading your SD cards? That probably makes it show up
> > as a standard /dev/sd device like other USB drives.
> >
> > I may be wrong, and it might not help you, but I think /dev/mmc is
> > enabled through the MMC_BLOCK option in the kernel, but even if you
> > enable that it may not change things if you have a USB bridge in the
> > way.
> >
> > On Windows there are some partition editors that show the state of
> > these bits. I haven't looked for a standard Linux partition editor
> > that does that but it's probably out there somewhere if you go
> > hunting.
> >
> > If you own a DSLR that supports whatever size SD card you are using
> > then it probably has a way to write protect cards while in the camera.
> > However if it's just a web cam that you're using it probably doesn't
> > but check the documentation.
> >
> > Good luck,
> > Mark
> >
> >
>
>
> Those deer trail cameras are somewhat cheap, ish.  Some of them don't
> even have a format option.  I have a old camera that the IR sensor
> doesn't work on, it never knows something is there to take pictures of
> so it does nothing.  Anyway, I use it to format cards with since most
> all trail cameras use the same format type and directory tree.  One
> partition and vfat.  Basically, it is really simple and not a lot of
> options.
>
> I use a card reader that hooks up via USB.  It's one of those multi
> reader thingys.  It's been a pretty good one but it isn't a real
> expensive one either.  Given I got the data off and plan to trash it
> anyway, it's not worth recompiling a kernel, rebooting and then hoping
> it will have the right device thingys.
>
> This thread has been interesting tho.  At least I know that a Sandisk
> card at least tries to fail in a way that I can get the data off that
> did get written to the card.  Hey, that's a lot better than some I
> guess.  :-D  I've had some other brands that when they die, they dead.
> You get nothing at all.
>
> Dale
>
> :-)  :-)
>

It's too bad that the little app I pointed you at doesn't work on your
setup. I'm going to look around for something more generic.

Keep in mind that the 'failure', if that's what it is, could be in
your trail camera if it glitched and set the read only protection in
the card by accident, or possibly something happened in the USB
bridge. I think you'd possibly be better served in the long run by
sticking this SD in a plastic bag and saving it until we can find a
way to check it out more. Won't cost you anything to throw it away
next year.

Happy New Year. Hope you get lots more fun trail camera pictures!

Cheers,
Mark