druck  wrote:
> On 30/04/2019 20:28, The Natural Philosopher wrote:
> > On 30/04/2019 10:30, Tauno Voipio wrote:
> >> On 30.4.19 10:36, The Natural Philosopher wrote:
> >>> On 30/04/2019 08:28, Tauno Voipio wrote:
> >> There is a bit in the SD card which can be turned on to
> >> write-protect an area, but it cannot ever be turned off.
>
> Sorry, that's rubbish, there is no firmware on an SD card to do this.

There is.  Look up the 'permanent write protect' bit in CSD bit 13.

SD cards are more than just dumb block devices, even if that's the way the
vast majority of people use them.  That's the raison d'etre of the 'Secure'
part of 'Secure Digital'.

> > It appears after a little research taht some SDC rcrds go readonly and
> > need binning.
>
> That is factually correct (unlike the spelling).
>
> >  It alos appears that this is the best chance to save them
>
> As you say, they need binning, don't try to save them.

If it's a high value card (say 512GB) it could be worth a try saving them -
getting the data off then doing a complete format with the SD Association
tool.  But I wouldn't use it for anything critical after that point.

If it's a small card I'd just buy a new one.

If it's gone Permanent Write Protect then I don't think the formatter will
help.

Theo

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