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On some m.2 SSDs, there is an unpopulated spot for a header at the screw end of the drive (as opposed to the edge connector end of the drive). What is the purpose and the pinout for this header?

See the pair of holes near where the screw is when installed, one of which has a square pcb pad around the hole, and the other a circular pad. That is what I refer to.

enter image description here

Giacomo1968
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Alexander M
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  • Good question...they appear to be a remnant of the initial board testing phase, like an external 3.3V supply. Anyone have such an SSD and a multimeter to check if it leads anywhere? – Natsu Kage Jan 31 '20 at 02:40
  • It's likely a serial header pad for testing the drive by the OEM or for flashing the drive's firmware via serial... contacting the OEM's tech support would likely render an in-depth answer – JW0914 Jan 31 '20 at 02:57

1 Answers1

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The headers are actually an SPI or an I2C interface I believe, for debugging. It is sometimes written DO and DI (Digital In, Out perhaps?) :

enter image description here

This is the same labelling as in SD cards for SPI communication: Example

Many SSD have more open pins for debugging, such as this one which is clearly labelled:

enter image description here

You can see this one has an option for writing to the ROM of the SSD as well as JTAG options.

People have checked an successfully communicated with these headers:

https://www.pentestpartners.com/security-blog/walkthrough-investigating-an-ssd/

Natsu Kage
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