In July 2019 I heard from Mik who had just picked up a D10D for $13 that he was intending to use as a NAS box along with running oVPN. As part of this exercise he wanted to use the second (unpopulated) SATA port on the motherboard and wondered if anybody had already done this. My answer was "Not to my knowledge" but I was able to point him at a similar exercise that Menno had carried out on a VXL thin client back in 2012. (See here). The key point that we found at the time was that there are four 10nF capacitors in series with the SATA data lines. If they've left the SATA socket off the board then it is almost certain that these have been omitted as well.
When his D10D arrived Mik went investigating. His report is below.
In September 2019 I heard from Piotr who had just picked up a really cheap D10D - no ram and no PSU but ~5€ with shipping. He also set about installing the second SATA port and his experience is here.
As far as the second SATA port goes it is visible in the BIOS and, using a multimeter, I was able to find where to solder 10nF caps. As per SATA specs you need 4 of them. The locations are marked in the photo. It turned out that two of them are under the heatsink so that has to be removed - maybe not such a bad thing as it gives you the opportunity to ensure that the thermal paste is up to scratch.
This photo is of the top of the circuit board with the heatsink removed. You can see the unpopulated SATA socket location about half way down on the left hand side.
This photo shows the detail of where the second SATA port is fitted (CN1701) and the locations (small square red boxes) where two pairs of capacitors have to be soldered in place.
After a short delay while the necessary components (SATA socket and 4 x 10nF capacitors size 0402) were ordered and delivered I received an update:
Operation has been completed and patient survived.
I had a bit of struggle soldering in the SATA port. I found I couldn't easily suck out the solder from the mounting holes for the socket, but after 2 hours of drilling with 0.5mm bit and sucking with a suction syringe I finally made it as you can see in the photo.
The capacitors go where I indicated previously. I took power for the drive from CN1700 and I used the exact same method and connector as Ammon - JST XH with 1.25 pitch.
Linux sees both my hard drives I had lying around - a 20GB and 750GB. That just leaves me to figure out how to mount the second one.
Note: Ammon mentioned above used a Dx0Q as a file server. See here for details.
Mik's experience with trying to clear out the holes in the board in order to mount the SATA socket echoes mine with the VXL client. It is not easy - you have been warned.
Any comments? email me. Added August 2019