[HowTo] Enable PCIe Gen2 to get max speed of NVMe @ RockPi 4b

bofibo · September 19, 2022

I will show you how I successfully enabled pcie gen2 on my Rock Pi 4b and now my nvme is running at 1.1 GB/s.

The solution which you can find on the web to activate pcie gen2 on an Armbian did NOT work for me:

sudo nano /boot/armbianEnv.txt

and insert:

dtoverlay=pcie-gen2

The following solution activated pcie gen2:

0. check your current nvme speed to compare it afterwards with:

sudo dd if=/dev/nvme0n1 of=/dev/null bs=1M count=2048 iflag=direct status=progress

--> 618 MB/s

1. find out which rk3399-rock-pi-xxx.dtb your Rock Pi 4 is using.

cat /boot/armbianEnv.txt | grep fdtfile

--> fdtfile=rockchip/rk3399-rock-pi-4b.dtb

--> In my example I will use rk3399-rock-pi-4b.dtb

2. make a backup of your *.dtb file

sudo cp /boot/dtb/rockchip/rk3399-rock-pi-4b.dtb /boot/dtb/rockchip/rk3399-rock-pi-4b.dtb.bak

3. copy *.dtb to /tmp

sudo cp /boot/dtb/rockchip/rk3399-rock-pi-4b.dtb /tmp/rk3399-rock-pi-4b.dtb

4. we need to make *.dtb into *.dts to edit it

sudo dtc -I dtb -O dts -o /tmp/rk3399-rock-pi-4b.dts /tmp/rk3399-rock-pi-4b.dtb

(4b). If you don't have dtc on rockpi than install it with:

sudo apt-get install device-tree-compiler

5. edit *.dts

sudo nano /tmp/rk3399-rock-pi-4b.dts

search with [Ctrl + w] for the string: max-link-speed

you will find something like this

Zitat

max-link-speed = <0x01>;

replace it with:

Zitat

max-link-speed = <0x03>;

save your file

6. turn *.dts into *.dtb

sudo dtc -I dts -O dtb /tmp/rk3399-rock-pi-4b.dts -o /tmp/rk3399-rock-pi-4b.dtb

7. copy new *.dtb to /boot/dtb/rockchip

sudo cp /tmp/rk3399-rock-pi-4b.dtb /boot/dtb/rockchip/rk3399-rock-pi-4b.dtb

8. give the file the same rights as before

sudo chmod 0755 /boot/dtb/rockchip/rk3399-rock-pi-4b.dtb

REBOOT

Now check your vnme speed again and if everything worked you should see 1.0 GB/s [ ]

sudo dd if=/dev/nvme0n1 of=/dev/null bs=1M count=2048 iflag=direct status=progress

--> 2134900736 bytes (2.1 GB, 2.0 GiB) copied, 2 s, 1.1 GB/s

"""THERE WE HAVE THE SALAD"""

"""B0F1B0"""

dgatwood · September 19, 2022

One reason that didn't work may be because it's a mix of the Armbian syntax and the Debian syntax. It should be:

overlays=[name of overlay]

But I see you also used a different maximum speed. Assuming that's not a typo, you can create a new overlay like this:

1. Save the following (assuming I didn't make any mistakes) as rockchip-pcie-gen2-updated.d2s (wherever):

/dts-v1/;
/plugin/;
/ {
model = "ROCK PI 4B";
compatible = "rockchip,rockpi", "rockchip,rk3399";
fragment@0 {
target = <&pcie0>;
__overlay__ {
max-link-speed = <0x03>;
};
};
};

2. Compile it:

dtc -O dtb -o rockchip-pcie-gen2-updated.dtbo rockchip-pcie-gen2-updated.d2s

3. sudo mv rockchip-pcie-gen2-updated.dtbo /boot/dtb/rockchip/overlay

4. Edit /boot/armbianEnv.txt and add

overlays=pcie-gen2-updated

or if you already have a line, add a space and add "pcie-gen2-updated". Note that you drop both the extension and the rockchip- prefix in the overlays field.

If that doesn't work, try changing &pcie0 to &pcie.