TRB500: Speed becomes capped to about 220mbps after some time


I’ve recently purchased a TRB500 to serve as my 5G modem gateway. As a developer and IT enthusiast I prefer to use enterprise-grade hardware for it’s stability and flexibility. First impressions were very good, this is really well built device with decent software which offers way more control than any standard consumer-grade hardware.

However, there’s one major issue.
I have a pretty good 5G signal. Right after booting up the device, I usually get somewhere around 400mbps download and close to 100mbps upload speeds.
However, after some time, download speed goes down to about 220mbps or so even though the signal levels remain the same. Rebooting the device restores the initial performance, but only temporarily.

Upgrading to the latest firmware does not help.
I found a couple of existing threads about this issue. There was a modem firmware update posted which supposedly includes a fix for this issue. I have tried installing it but this did not change anything.

Further digging in SSH shell confirmed what was already posted in one of the topics - after some time NAT acceleration stops working and the network speed becomes CPU limited. Since the main processor is rather weak, this severely limits network speed.

This bug badly needs a fix as it essentially cripples the performance of an otherwise really decent modem gateway.
Any solutions ?

If you need any shell command output, exact software version numbers, etc. I can post them here, just let me know what you need.

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Its first time I’m reading about this and interested if this happens also on RUTX50.
Can you share your commands what you used and what to look for?

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This AFAIK is a known issue with this model. There were already topics posted on this. There was a firmware update from Quectel which supposedly fixes the issue but as I have already mentioned, installing it had no effect for me.
Not sure about the router version as, while it uses the same 5G modem, it has a different architecture with a separate CPU for the main OS, while TRB500 runs the main OS on 5G modem’s CPU.

I really expected better quality software from an enterprise-grade device costing almost 400 EUR.

Still hoping for a solution. I will try running the modem in pass-through or bridge mode to see if anything improves.


I have the same problem as you and am currently trying to resolve my issue with Teltonika support,

I personally advise you if you can return your TRB500 to do so, unfortunately it is not possible in my case,

apart from that I have already been offered to update the firmware via CLI/SSH, but it did not work and the support tells me that I performed the update incorrectly, despite the fact that the CLI console indicates that the update was correctly installed,

so I give you the procedure to do for the update in the hope that it will help you:

"I would like you to perform a mobile module firmware upgrade since currently RG501QEUAAR12A08M4G_04.200.00.000 is used, which is not the most recent and we have several similar issues captured on this specific firmware as well.

The procedure is as follows:

Connect the device to the internet via a Wired WAN connection (internet connectivity is mandatory, and it must not be from the modem, since it will be disconnected during the firmware upgrade).

Disable the “Ping Reboot” and/or “Auto Reboot” services (if you have them enabled)

Navigate to the System → Package Manager → Packages page and install the “SSHFS” package

Once the “SSHFS” package is installed, connect to this device via SSH/CLI and execute these commands:

opkg update
opkg install modem_updater

modem_updater -g

The last command will list available firmware versions. Next, modify the following command:

modem_updater -i (ID) -v (VERSION)

(ID) - should be 1-1.4, 3-1 however, in case of an error you should be shown a correct ID.

- enter the latest firmware version from the list of the previously executed command.

Please wait until the modem firmware upgrade finishes, do not reboot or power off the device while the firmware upgrade is in progress."

Best regards,

I would also like to point out that the problem comes from the internal firmware of the TRB500, the support recognizes it themselves.

Thanks for your response, glad to know this problem hasn’t been abandoned and they are still working on it. I will out try your instructions and report back.
I got the TRB500 because it was perfect for my use case. I needed a decent quality 5G modem/router and I didn’t care about WiFi. Also, as a Linux geek, I like the advanced features and the level of access this device offers. And of course, since Lithuania is my home country, I wanted to support a local enterprise.
My TRB500 is only used as a secondary connection so it isn’t critical to have the modem working well ASAP.

I cannot return the device as more than 2 weeks have passed since the purchase date. All I could do now is RMA which I do not plan to. I’d rather help debug and have the device fixed.

I understand you, I also took this router for its many interesting features, I don’t plan to give up either,

In addition, the support provided me with an explanation on the problem that I encountered when I updated the firmware of the TRB500, the update was correctly installed but it was an old version " RG501QEUAAR12A07M4G_04.001.00.000" unfortunately it was the only version offered on CLI, I should have found normally “RG501QEUAAR12A09M4G_04.200.04.200” or “RG501QEUAAR12A10M4G_04.200.04.200” which are the new versions with the fix for the problem,

so let me know if you have the same problem as me, support should give me a solution to the problem soon, I will also keep you informed if necessary,

Best regards,

Ok, reporting back.
modem_updater -g found “RG501QEUAAR12A07M4G_04.001.04.001”, the old version which would not flash.
The only other version I have is RG501QEUAAR12A08M4G_04.200.04.200 (modem_update_trb500.bin) which still has the speed issues.

So I need either firmware RG501QEUAAR12A09M4G_04.200.04.200 or RG501QEUAAR12A10M4G_04.200.04.200 to fix the speed issues. But neither of these two are available via the updater.
Let me know when you get a solution from support.

Ok. I’m too impatient to wait.
Did some digging in their modem FTP, found firmwares RG501QEUAAR12A09M4G_04.200.04.200 and RG501QEUAAR12A10M4G_04.200.04.200. Grabbed the update image for the A10 firmware and hacked together an update file to match the format used by the updater. The file flashed fine via the web UI, modem seems to work fine, UI reports new version.
Now, let’s see if this version fixes our speed issues.


I hope the firmware RG501QEUAAR12A10M4G_04.200.04.200 correct the problem, if this fixes the problem could you give me a link so that I can also download the firmware for my part.

Best regards,

8 hours since last reboot under normal usage, still getting good speeds. Will monitor for a while longer and report if this changes.
Firmware RG501QEUAAR12A10M4G_04.200.04.200 is available on modem FTP (that’s what modem_updater uses) but it’s a raw modem partition image from Quectel. I have manually put together a compatible update file from it. Not sure if it’s OK to post it here, since it’s not an “official” update.
But I can send it to you privately if you want.

Yes I would like you to send it to me privately, thanks

Send me an email to postas [at] raspis [dot] eu I will send the file it to you.

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