![]() ![]() ![]() These cards don't prohibit CMD26 in SPI mode and therefore allow writing the CID. I got a few emails pointing out that using the CID as copy protection is not a good idea because there are some cards on the market which are not compliant with the standard. To convert the hexadecimal number to a binary one, please have a look at my multiplatform Binary/Decimal/Hexadecimal Converter.īased on an iMX233 CPU Board it may be easy to build an intelligent USB card-reader, supporting, for example, CID / CSD information and autonomic card tests. The resulting hexadecimal number contains the following information: On my Olimex iMX233 OLinuXino embedded Linux board I call the following (directly on the board): cat /sys/block/mmcblk0/device/cid So I check the CID using the adb tool from the Android SDK (rooting is not necessary): adb shell devices/platform/s3c-sdhci.2/mmc_host/mmc1/mmc1:b368/block/mmcblk1 devices/platform/s3c-mshci.0/mmc_host/mmc0/mmc0:0001/block/mmcblk0 It can be used as CID decoder without SD. I suggest you make a note of the old CID first, in case you want to set it back later. CID decoder is activated by pressing button with a question mark next to CID number or from Menu View/CID register. ![]() Unfortunately, you cannot know the real path of the SD card in the /sys file system so I can only give some examples and you have to try out the actual path yourself.įor example, on my Samsung Galaxy Note running Gingerbread, there is a /sys/block/mmcblk0 soft link pointing to: mmcblk0 ->. If you only need to change the card serial number (part of the CID) you can supply the old CID and the new serial number and the new CID will be calculated for you. Luckily the Linux kernel provides the CID via the SD and MMC Block Device Attributes so you may use a Linux device containing a direct SD interface like your Android phone or an embedded Linux board. Back to the main interface, click Apply to commit the pending operation. In the pop-out window, you can edit a new serial number such as 123456. Right click the SD card partition, and click Advanced and then Change Serial Number. My iMX233 based development board has 2 of them, so it was an easy task to improve our firmware to read the CID and extract the serial number, but how do I check if I get the correct information? Reading SD-Card SID Install and launch AOMEI Partition Assistant Professional. Unfortunately, it is not possible to read the CID of the card with a USB adapter - you need a \'direct\' SD interface. The serial number is stored in the Card Identification Register (CID) which is read by \'Command 10\' as stated in the SD Simplified Specifications. For my current project, I tried to read the SD Card serial number because the number is factory stamped and unchangeable, so it easily could be used to protect embedded firmware from being copied. ![]()
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