RM520N-GL RGMII Ethernet port issues/drops

Hello there, I am using an RM520N-GL in an M.2 to RJ45 board (RGMII) and I’m having some trouble with the Ethernet port. It simply just stops responding to packet requests. It’s noticed the most when the modem is in motion, moving to different cell sites.

The only way to fix it temporarily is to reboot the modem.

I know that the modem is still connected to the Internet when this happens because I can access the gateway through tailscale (static binary running directly on the modem)
Tailscale isn’t causing it to happen either, it happens either way.

Anyone know the fix? Does Qflash on windows do a true full flash of every partition on the modem? If not, how can I do so? Thanks!

I’m thinking I know what it is.
I changed AT+QETH=“RGMII” from Enabled to Disabled last night by sending AT+QETH=“RGMII”,“DISABLE”,1

I also set it into ECM mode AT+QCFG=“usbnet”,1

I drove around with it today and didn’t have any issues. I’ll keep an eye on it.

Can you tell details about the “M.2 to RJ45 board (RGMII)”? Is it something off-the-shelf?

In my case curious problems/USB line drops were related to power supply issues,
the power supply were not able to supply enough current to when the radio module was doing something/more than idle.

Yeah. So the board I’m talking about it’s starting to get very popular. It’s kinda like a USB M.2 adapter but it also gives the module an Ethernet controller with an Ethernet port (RJ45) to use. I like the one from Aliexpress by MCUZone. Has a 2.5Gig Ethernet port, USB C 3.0 for both power and data, and a 12v port for power. I use the 12v port with a 12v 5a adapter.
They also just came out with a PoE version as well.

would you provide link of the product. K.R.

does this product support both PCI and USB products of RM520NGL?

I bought PCI onne :sweat_smile: :sweat_smile: :sweat_smile:

note:
pci:RM520NGLAP-M20-SGASA
usb:RM520NGLAA-M20-SGASA

https://a.aliexpress.com/_msNEeTu

No idea. I can tell you that part of the process is to set data communication to PCIe mode. May or may not work. I don’t own the pci version of the module

I think I am experiencing the same issue. My modem is an RM502Q-AE running firmware RM502QAEAAR13A03M4G. I think I’m using the same mcuzone m.2 → 2.5g eth enclosure and powering it the same way (12v adapter).

I am not driving around with mine; presumably it stays connected to the same cell site the whole time.

When ethernet connectivity fails, I can still connect to the modem via the adb shell (over usb). In the kernel ring buffer (linux running on the modem), I see:

[131274.081467] eth0: pci link is down
[131274.081467] .
[131276.081392] eth0: cmd = 0xff, should be 0x47
[131276.081392] .
[131276.081522] eth0: pci link is down
[131276.081522] .
[131278.081443] eth0: cmd = 0xff, should be 0x47
[131278.081443] .

I can still ping things on the internet (e.g. 8.8.8.8) from the modem.

My suspicion is that something is wrong with the r1825 kernel driver that is supplied with the modem’s firmware. I suppose it could also be something amiss with the mcuzone enclosure, but I have not sought a different rgmii enclosure to confirm.

Yes I have seen the same thing going on with dmesg.

Check this out too:

cat /sys/kernel/debug/ipc_logging/pcie0-short/log

The PCIe link is being interrupted it seems.

msm_pcie_handle_linkdown: PCIe link is down for RC0

I have found that setting AT+QCFG=“data_interface”,0,0 also helps. I guess this isn’t really needed for a working setup.

I believe in the hardware design notes it does mention that for a PCIe link it should be the shortest distance to the chipset possible.
This smaller board seems like a good place to start: https://a.aliexpress.com/_mrA4Gyq

I have a Quectel 5G M2 EVB kit with an RTL8125 module on the way for testing.

I look forward to hearing your findings.

I wonder if someone from Quectel could weigh in here.

@herbert.pan-Q Can you help or find someone who can?

Support’s perspective is: They have no control over the MCU board. So gotta get an EVB kit with the rtl8125 addon and test with it.
“Please check if the physical PCIe connection is stable and examine if there is any signal interference near the PCIe routing. PCIe signals are high-speed, requiring high hardware wiring standards. Please measure the PCIe eye pattern to confirm if the PCIe line signal quality meets the requirements.”

I mean, that makes sense, but I certainly do not have the tools and skills needed to assess that sort of thing. To my eye, the mcuzone board and enclosure seem to be well made. :-/

iamromulan -
were you able to get the EVB board’s NIC working?
I have the LGA - RG530F-NA along with the 5GDM02 EVB Kit. I am waiting for the instructions from Quectel’s support to configure this modem for the onboard NIC, but after changing the pcie_mode and usbnet values based on other m.2 modems I’ve played with, the NIC link lights don’t come on.
I also had issues with the MCUZone boards. Anytime heavy throughput was generated, it would knock the network interface offline. This was while stationary and not even in motion (yet). USB seems the most stable, but offers the least flexibility when building our own gateways.

I ended up getting the “OG” board as I call it before I got the EVB board. https://a.aliexpress.com/_mMlohfE

If you notice the m.2 slot is placed as close as possible to the Ethernet chipset. I think this is the big problem with the MCU boards.

I honestly haven’t used my EVB yet at all. I was able to determine it was the MCUzone board causing the issue.

There is a new board that just arrived that has excellent build quality and no issues. I’ve been testing it and I can honestly say the MCU board was holding back my speeds. Check it out; Dual SIM, passive PoE, big ol’ aluminum block for keeping the modem cool.
You can get it for $50 shipping included from the source at https://rework.network/

He’s on vacation at the moment though, wireless haven is selling it for $10 more

The seller is still teasing us on this board availability. Today is July 26 and his AliExpress page still not working.

:joy:
He’s probably not ready to open up shop again yet. I’ve bought a few boards from him already. They are legit.
Wireless haven bought theirs from him as well.

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thanks for the recommendation! I have now gone through 2x mcuzone boards and both are problematic. I just pulled the trigger on the one you just recommended. Love this diy stuff! love your code repo, as well. I will be using the rm521f.

Thanks for the information. Unfortunately the Wireless Haven is only serving the USA. I wish I could get one soon because I really want to get rid of my old WG1608 router I suspect it is significantly limiting my speed.

Link to shop is back open as an alternative Wireless.