Radxa M.2 E key to SATA breakout card


is it compatible with Rock 5A?

Yes, it is. And there will be m.2 E key to M key 2280 extend board for 5A as well. Also works on 3A.


I have tested this feature with a M.2 E key to PCIe x1 converter, followed by a 20 port sata card. This works with Debian 11, but it doesn’t work with Manjaro:

Great :slight_smile:
Are there any chances for m.2 splitter for Rock5B? Some cards uses 2x or 1x pcie lane, should be easy to split that to 2x2 or 4x1


i would like that as well. I would like to split the M.2 M-key PCI-e x2 port of the RockPi3A into 2 separate PCI express 3x1 slots, so I can connect a nvme SSD on one PCI-e lane, and a 2.5 Gb or faster network card to the other lane. The bandwidth of a single PCI-e 3 lane is 0.985 GB/s, so it’s almost possible to run a 10Gbit network card at full speed on that.

Does the kernel understand such splitting?
Does Aliexpress sell such splitters?

As we discussed here soc supports that and it should be possible to split into 2+2 as well as further splitting into 1x lanes. There are many such pcie cards for 8x slots, I found only one or two for pcie 4x and none for m.2 slot. For now to test that You would need m.2 to pcie adapter:

and then bifurcation adapter:

and probably some ribbon cable or insert that on rock 5B.

The main problem here is that pcie 4x bifurcation adapters are not popular, usually people splits 8x and 16x pcie. Here we fight for each pcie lane and would need something small from m.2 to 2x/3x/4x m.2. The best compact adapter was the one made for khadas vims:

or the one on ribbon:

they both are fitr perfectly on small khadas board, and they are very cheap. The one without ribbon is so simple that it slides into m.2 and gives two m.2 ports (of course it basically just extends signals from them, and it’s 1x pcie 2.0 AFAIR).

Also I found out that there are many very cheap splitters on pcie 8x.
This card is about $20

it’s on ASM1182E, cards for 4x slot are on ASM1812 and ASM2812 for about $60
I know that some people are using 8x pcie cards on pcie 4x slots, with such adapters:

(or by just drilling limiter on side of 4x slot),
but don’t know how this will work - slower or only one slot.

I made a little PCB which splits the x4 Lanes into 2x2:

I haven’t tested it yet. I ordered the wrong thickness (should be .8mm, is 1.0mm) and i still need to find out how to modify the PCI-E configuration in Linux. I’m still not sure what to do with the signals wake, clkreq and perst because they only exist once on the Radax M.2 port. The pins on the RK3588 intended for this signals for the second PCE-E port are already used otherwise
In the end it should look something like this:

It’s intended for a NAS with a PCI-E to SATA adapter and an NVME SSD


The second one is totally worth its money, for m.2 to x16 slot

I use this 15€ one for my nas-build with
SATA controller: JMicron Technology Corp. JMB58x AHCI SATA controller
for a month without any problems so far.

@Semi This is a great idea, can you please keep us updated. Thank you very much.
The original M.2 E key to SATA breakout card is out of stock at allnetchina, does maybe some mod know if another production batch is planned soon?

This is exactly what I meant :slight_smile:
I would just place m2 on left of rock5 m.2 or rotated by 180 degrees on the right side so it would not extend of sbc.

I think that also 2x + 1x + 1x would be nice product and maybe 1x1x1x1x (but this one for smaller nvmes like 2230 modules that are cheaper and much more faster than sd cards today.

Any progress on Your m.2 splitter card? :slight_smile:

Yes i did make some progress. I made a new PCB which now fits completely under the Rock5. I am able to boot from an NVME-ssd connected to two lanes while a JMB585 sata controller is connected to the other two lanes. I’m planning to use it as a NAS but i have only made some experiments, so i can’t say anything about reliability, especially since the power stage was designed for only one device.

You can have a look at the files here:
Files (altium.com)


Looks just perfect, thanks for sharing this!
@jack @RadxaYuntian @hipboi @setq please take a look at this, any advices or similar product planned for RK3588 boards?
There should be also possible to do 1x 1x 2x board
@semi thanks for your hard work, looking forward for any test result too :slight_smile:

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Thank you very much for sharing your design with us, it looks perfect and I am happy to try out a solution similar to yours, using the Rock 5 as a NAS with Sata and a NVME.

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I tested two 5-Port jmb585 controllers in m.2 format. I consistently get problems after a couple of hours, especially if I move around a lot of data or read a lot of data (test case is usually first moving a couple hundred gb from one drive to another and then scan a plex library). Timeouts, drives spinning down and spinning up, finally leading to readonly failing filesystems. I ruled out: cabling, drives, cooling of the jmb chip (still not sure, that’s a ridiculous small heatsink), and power supply.
I’m using armbian, booting from sd, rootfs on drive 1 (SSD) and the 4 others are spinning rust.
Anyone else having problems? I’ll attach a log once i’m back at my main workstation.

This adapter looks interesting for me, have you tested two nvme ssd on this?

@Semi Have you thought of using an ASM2812 (or PEX8712 / PEX8714) PCIe Gen3 Packet Switch to get either 2x4 or 4x2?

I also wonder whether having 1x4 and 4x1 with such a switch is possible so that we can have a full x4 slot for either ssd or gpu and four x1 slot for wifi card, sata card, or even multiple 2.5GbE (or 5GbE) LAN card.

@dominik do you think it is possible to do a 3 slot splitter that can work either in 2x 2x or 2x 1x 1x?

For example first two slot will be 2x slot, if both slot has 2 lanes device plugged in, the third slot will not work, but if the second slot got a 1-lane device plugged in, we can plug a 1-lane device on the third slot and config the rock 5b in 2x 1x 1x