I searched but could not find the answer to my question. What I want to know is this: do SD cards have internal flash ROM that enables the SD card to communicate/interface with a SD card reader, computer, etc or does it use a dedicated controller of some kind?

The background is that a USB drive does have flash ROM which contains code to allow the USB stick to interface with the USB port. That ROM can be compromised by a virus so is the same kind of compromise possible with a SD card?

I hope my question is not too ambiguous.

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    \$\begingroup\$ Bunny Huang was done extensive research in this area. There is not a blanket yes or no answer since each manufacturer does different things. Technically, ROM cannot be altered, but EEPROM and flash can. You might might want to tighten up the scope if your question if you want a more precise answer. \$\endgroup\$
    – Kartman
    Oct 26, 2021 at 23:27
  • \$\begingroup\$ Most cards have a dedicated controller that stores necessary data to implement a disk drive on the flash memory. \$\endgroup\$ Oct 26, 2021 at 23:32
  • \$\begingroup\$ @Kartman, thank you for the tip. I read through Bunnie's pages and got the answer that I was looking for. \$\endgroup\$ Oct 26, 2021 at 23:56

1 Answer 1


SD card controllers might have internal flash or just use the data flash for storing the program. Anyway, one way or another the SD card controller might execute firmware which has the algorithms for managing the data blocks wear leveling etc on the data flash. They might even contain bugs as some card manufacturer supplied a firmware as a batch of cards kept corrupting their contents.


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