Killer M.2 extender board -Literally


Received my new shorter M.2 extender board yesterday with no instructions. It comes with 2 ribbon cables, which are longer for folks who intend to mount the board on top of the SBC (improving access to the microSD slot). I noticed that the contacts on the ends of the cable are now on opposite sides.
But, when I examined the board’s M.2 connector, I could see that the contacts grip the ribbon cable on both sides. In other words, it doesn’t matter which side of the ribbon cable has exposed contacts, from an electronics perspective.

So, I used my original shorter cable because I am customizing an aluminum hobby case and the longer cable doesn’t fit and would make the microSD slot inaccessible (too far inside the case to reach). I left the board’s orientation the same as before. In other words, the only difference is that the M.2 connector is on the opposite side of the board, but pin # 1 would be the same… so I thought.

When Radxa remounted the M.2 connector, they also reversed the pinout order!

Now, I have a dead Rock Pi 4B. Most likely, the $270 Samsung 1TB NVMe is dead too. All parts included, I’m out $500 now.

Perhaps @jack or @luffy… someone should inform Radxa that they need to provide their customers with some installation instructions, which includes a fair warning that the pinouts on the new M.2 extender board have been reversed. That would have avoided this from happening.

Doubt if you folks will be hearing any more from me in the future. Thanks to all of you who have been so helpful. Best of luck in your endeavors.


I just received mine too, no instruction whatsoever, checked allnet, no instruction either. @jack you really need to post the instructions somewhere accessible, the installation is not an intuitive process.

Besides, since you are providing 2 ribbon cables, why not include a shorter one so it won’t stick one inch out of the edge when using regular standoffs?



I am really sorry for this. Indeed we did not thought people would mix the cables. We will put the instructions on the wiki:

The pinout is reversed because the connector is now at the bottom, the routing is straightforward if we reverse the pintout. So the FPC cable is changed to pin on dual sides.

I am sorry for your loss. We will send you another ROCK Pi 4. For the Samsung SSD, I am not sure the warranty in your country. Here in China, we can replace for a new one within 3 years.


@jack Thank you for replacing the Rock Pi 4B w/4GB.

The longer FPC cable won’t fit inside a case, while allowing the microSD slot to be within reach. Of course, as others have mentioned, if the M.2 extender board is mounted above the Rock Pi’s mainboard, the FPC cable blocks access to the microSD slot. Radxa kindly provided the longer FPC cables at their requests, but as I’m sure they have discovered, the longer FPC cables are literally a work-around solution, which is still less than ideal.

These issues are solved by mounting the M.2 extender board under the heatsink, using the shorter FPC cable. The shorter FPC cable is ideal, provided that customers known to turn the board upside down (to reverse the pin order, matching the shorter M.2 extender board’s pinouts). This configuration also improves thermal isolation between the SSD and heatsink, because it places the SSD on the opposite side of the extender board from the heatsink. Of course, with the Rock Pi, large heatsink, and SSD being enclosed inside a case, cooling fans are being implemented to provide adequate airflow between the heatsink and SSD (illustrated in the following photos)

There is no indication of pin #1 on either the M.2 connector nor FPC cable. Furthermore, the M.2 connector is double-sided and the FPC cable can physically be inserted either way around. This is confusing, so it would be very helpful for the M.2 extender board to include illustrated instructions in the packaging.


Hi, @jack .
Provided link really broken, no content there: