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How do I figure out the brand and type of an SD-card remotely on the commandline via SSH? I so far tried:

  • fdisk -l /dev/mmcblk0
  • gdisk -l /dev/mmcblk0
  • dmesg | fgrep -i mmc (the boot entries were already rotated out of the ring buffer)
  • zfgrep -i mmc /var/log/syslog* /var/log/kern.log*
  • smartctl --info /dev/mmcblk0 (resulted in /dev/mmcblk0: Unable to detect device type)
  • lshw -C storage
  • file -s /dev/mmcblk0
  • cfdisk /dev/mmcblk0
  • cgdisk /dev/mmcblk0

Context: After having had to replace SD-cards in two of a bunch of remotely deployed Raspberry Pis (LoRaWAN gateways) which were not initially installed by myself, I want to figure out if the remaining, still running Pis have the same type of SD-card or by chance a different brand and/or type.

A bit of information I figured out, but I didn't find a mapping to brand or type, i.e. something that I can correlate with what I can see from the outside of the two broken SD-cards:

# cat /sys/block/mmcblk0/device/name 
SU04G

# cat /sys/block/mmcblk0/device/name 
SS08G

# cat /sys/block/mmcblk0/device/name 
ACLCE

# cat /sys/block/mmcblk0/device/name 
SL16G

So they seem to be different (the numbers before G—where present—correlate with the size), but are they also different manufacturers/series?

At least this always looks the same on all of the four Raspberry Pis from which the four different name contents above were taken:

# cat /sys/block/mmcblk0/device/oemid 
0x5344
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2 Answers 2

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Some data, as you mentioned, is in /sys/block/mmcblk0/device. There's a tool called mmc in the mmc-utils package that can read/decode several of the values in that directory. For instance:

$ mmc csd read /sys/block/mmcblk0/device
type: 'SD'
card classes: 10 switch, 8 application specific, 4 block write, 2 block read, 0 basic, 
capacity: 14.76Gbyte (15847653376 bytes, 30952448 sectors, 512 bytes each)

$ mmc scr read /sys/block/mmcblk0/device
type: 'SD'
version: SD 3.0x
bus widths: 4bit, 1bit, 

$ mmc cid read /sys/block/mmcblk0/device
type: 'SD'
manufacturer: 'SanDisk' 'SD'
product: 'SS16G' 8.0
serial: 0x95554991
manfacturing date: 2017 jun

You can also pass -v to any of those commands to get lower-level details on how the data was parsed.

Unfortunately, I haven't figured out if any of the other functionality works on regular SD/MMC cards, or just eMMC. e.g. I can't get sudo mmc extcsd read /dev/mmcblk0 to work on my Pi. But, with your mention of sysfs I was able to get the tool to parse some of the other data!

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  • Indeed, thanks! I guess this is the closest we come with this topic. Thanks again!
    – Axel Beckert
    Mar 28, 2022 at 23:54
  • sudo apt install mmc-utils -y && mmc cid read /sys/block/mmcblk0/device did it for me, thanks
    – Radu Ursache
    Jul 16, 2022 at 21:07
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0x5344 from the oemid means SD as in SanDisk. Type is probably not easy; I guess it is their internal name. Read more at https://www.cameramemoryspeed.com/sd-memory-card-faq/reading-sd-card-cid-serial-psn-internal-numbers/

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  • Thanks a lot for that link. That even explains some more of the information I can find in /sys/block/mmcblk0/device/ on Linux. And indeed. hex 0x5344 is "SD" in ASCII. So they're all from SanDisk, but all different models. Now I just need to find a table of there 5-character product names. Oh, and welcome to the site!
    – Axel Beckert
    Feb 23, 2021 at 6:44
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    @AxelBeckert: Some more information is here, and in the "appendix" which follows. There is more data in /sys/block/mmcblk0/device/csd, but neither blog helps decode it.
    – Seamus
    Feb 24, 2021 at 23:37
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    You can use the mmc tool from mmc-utils to decode the csd data: mmc csd read /sys/block/mmcblk0/device gives something like: type: 'SD' card classes: 10 switch, 8 application specific, 4 block write, 2 block read, 0 basic, capacity: 14.76Gbyte (15847653376 bytes, 30952448 sectors, 512 bytes each)
    – Rylie Pavlik
    Mar 28, 2022 at 14:36

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