[GLLUG] Read only?

John Hearns hearnsj at gmail.com
Tue May 24 11:28:43 UTC 2022

Talking about SD cards, the satnav on my Volkswagen used a full size SD
I bought an up to date SD card - which is not read by the system in the car.
It turns out there is something called CID Locking - the manufacturer is
encoded as a CID number on the SD card.
Any other type of SD Card even though it has a valid filesystem does not
have the manufacturer CID and is rejected.

I read that you cannot use a USB card reader to set or reset the CID.
Does anyone have ideas?  Desktop PCs with 'real' SD Card readers must be
rare as hens teeth these days.

ps. I have used a USB SD Card reader under Fedora Linux

On Tue, 24 May 2022 at 12:24, James Dutton via GLLUG <
gllug at mailman.lug.org.uk> wrote:

> Flash devices go read only when they detect themselves that they have a
> fault.
> SD cards are not particulary reliable.
> So my best guess is that this has happened to your sd card.
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