Cheap LTE router for OpenWrt

Hardware Questions and Recommendations
1

Hello,

I know there are several threads that covers this question, however the only recommendation for that was to buy some cheap'o router and then equip it with USB 4G Dongle.

I want to ask if something has changed in this matter. I would want to simply avoid the need of adding the USB modem to the router itself.

Is there any (quite cheap) 4G LTE router that works well with OpenWRT?

I dont need crazy speeds, i just want to use it with ZeroTier in my garage to get the CCTV and alerting working.

Thank you in advance.

2

I'd use a used an old cell phone instead, most people own one of those.

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3

If the issue is getting a dedicated USB modem for the router, you might want to try digging out an old Android phone and have it play "USB modem" by tethering through USB (and powering/charging it through USB at the same time). With the added benefit that you can use a somewhat long USB cable and position the phone somewhere with good reception.

Anecdotally: In 2020 my DSL line broke and while waiting for the ISP to fix it, I relied on an old-ish Motorola G4 for my internet uplink for several weeks, without any issues whatsoever. I was able to go some 3 or 4 meters through long USB cables and extensions to improve reception.

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4

My only concern with additional USB modems is reliability. I guess the routers with built-in 4G modems could be more reliable than messing aroung with the USB sticks, but i might be wrong.

I dont mind the size, power consumption or other matters. It will be hidden somewhere in the garage anyway. I just want it to be reliable so i dont lose the CCTV vision every X days :slight_smile:

5

if there are any outages, it's usually because of the ISP, some cut the connection after X hours of inactivity.

6

@frollic's suggestion is excellent - it is possible to literally hook up an android phone to the usb port of an OpenWrt router and use the phone's 4G connection.

7

The answer to that will probably depend on where you are, what your skill level is, and what you consider cheap...

Personally I think the ZTE MF286D is a great candidate. Note the D though. It looks the same as other MF286 variants, but the internal hardware is totally different.

It works perfectly with OpenWrt (except for the unsupported phone/ATA ports) But unfortunately installation requires soldering a console, so it's probably not an option unless you are comfortable with that.

If you are, then there are plenty of MF286Ds available second hand in markets where the local operators sell them . I got one here in Norway for about EUR 50. Which I believe is as cheap as you can expect any functional LTE router. This one is actually quite powerful, being based on an IPQ4019 SoC and MDM9250 cat 12 modem.

I'd be careful with Ali express etc, since there are so many lookalike versions and many sellers speculate in confusing descriptions. Try instead to find one on some local marketplace if possible.

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8

I got a TP-Link TL-MR6400 for my mother and installed OpenWRT. I think it's working pretty well. At least she's been of my hair ever since I made it reboot overnight.

9

This ZTE looks great, however it is a little bit overkill for my needs (and its around equivalent of 90 euro currently second hand in my country - PL). I am fairly convenient with soldering, that would not be an issue.

There is a lot of 286R versions, however as far as i can see they are not supported by OpenWrt. I think i will snipe for the D version from now, in the meanwhile i will try to use the old android as a tether device as you suggested just to see how reliable it is.

Thank you guys for your quick help and involvement. You're the best.

10

Note that the modem in the 286R is reported to have some issues: Problem with modem in ZTE MF286R - #40 by fd0e

This is most likely caused by crashing modem firmware and not something that can be fixed in OpenWrt.

11

Tplink mr200 is very stable for me and got it for around 20euro. You just need to be carefull for the initial flashing and be prepared to use a eeprom writer (or and rpi) to unbrick it if needed.

12

is lte modem working stable on wrt, like official firmware?
also is firmware/drivers of the lte modem the same in wrt?
i'm asking because i have this device, i like how lte modem work under official firmware, but i don't like the wireless options

13

The modem is stable for me at least. No problem keeping a connection up for weeks.

It looks like a pretty standard Qualcomm MDM9250 modem. It's configured for QMI (RMNET) by default. I haven't explored any other mode, if at all supported. The modem firmware is stored on flash on the modem module, so it will be the same on OpenWrt as in OEM. Both OEM and OpenWrt use the qmi_wwan and option drivers, although the OEM versions obviously are modified. The qmi_wwan driver takes some parameters I never added (I am the original author of this driver):

bjorn@miraculix:/tmp$ modinfo  _rootfs.extracted/squashfs-root/lib/modules/3.14.77/qmi_wwan.ko 
filename:       /tmp/_rootfs.extracted/squashfs-root/lib/modules/3.14.77/qmi_wwan.ko
license:        GPL
depends:        usbnet,usbcore,cdc-wdm
parm:           bridge_mode:bool
parm:           debug:bool
parm:           bridge_addr:charp
parm:           qmap_agg_packet:int
parm:           qmap_agg_debug:bool

From the parameter names I assume the changes are related to QMAP (which is supported in the OpenWrt driver too, but can be hard to set up) and bridging. Which isn't supported by the OpenWrt driver because there's really no point - this is not an ethernet device..It can only route packets. But you can emulate a bridge with some restrictions, like the OEM driver probably does. However, you can do this just as easily without putting the code into the driver.

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14

Which version V1, V2, V3, V4, V5 or V5.2?

15

only v1 is supported https://openwrt.org/toh/tp-link/archer_mr200