Turn on the TMP\PERM_WRITE_PROTECT bit in a Micro SD Card

As the title implies, I am looking for instructions to permanently turn on the PERM_WRITE_PROTECT bit on a Panasonic 32GB MicroSD card (Class 10), so that no data can be written to the card, regardless of the machine it is placed in.

I am also looking for instructions on how to manipulate the TMP_WRITE_PROTECT as well, for a different set of the same type of SD Cards.

Any input is greatly appreciated!
Sean Plemons Kelly, CISSPInformation Systems Security EngineerAsked:
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nociSoftware EngineerCommented:
These are not high level commands, but settings of a so called CSD register on the cards.
You will need access to the SPI bus to access that register, that may require a low level controller programmed for this.

Like this:   http://www.seanet.com/~karllunt/sdlocker.html   (this does only TMP write protect...

http://www.seanet.com/~karllunt/sdlocker2.html  - description for password setting.

Specifications here:

Be aware that not all cards implement the full spec... (of report the size correctly :-(   )
Sean Plemons Kelly, CISSPInformation Systems Security EngineerAuthor Commented:
@noci - Mr. Lunt's site is actually where I found out about it (well, really from lifehacker which linked me to those).

Unfortunately, he talks about the Permanent setting, but doesn't delve into detail on how to set it (ideally, I would create a hardware solution similar to his SDLocker, but instead of temporary, it would set the permanent bit).
nociSoftware EngineerCommented:
From here: https://www.sdcard.org/downloads/pls/
Download: Part1_Physical_Layer_Simplified_Specification_Ver6.00.pdf  
Page 164: near the bottom shows the PERM bit is @bit 13, the TMP bit is @ bit 12.

So the firmware needs to be changed for that.

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Sean Plemons Kelly, CISSPInformation Systems Security EngineerAuthor Commented:
Superduper, thank you much!
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