Hi guys,

I've been stalking you for a while, but this is the first issue I haven't been able to solve by looking at your docs. Before I start I just want to let you know that your work is much appreciated! Keep it up! :-)
If this is not the right place, I would be happy if someone could point me in the right direction.

I have a problem setting up a Huawei E353s-2 3G modem on a TL-MR3020 router. My goal is for the router itself to use the 3G dongle to send data, so networking outside the router is not necessary. The router is running attitude adjustment (12.09, r36088) and no custom builds.

It seems like the usb_modeswitch kicks in fine and converts the device from 12d1:1f01 to 12d1:14db (as per the device specs). And dmesg shows that the right generic drivers are loaded and one usb interface is set up to /dev/ttyUSB0.

As far as I can see there should pop several USB devices up in the tty directory, but if I manually load the option drivers (by writing 12d1 14db to /sys/bus/usb-serial/drivers/option1/new_id -- see dmesg below at ~361) a new device shows at /dev/ttyUSB1. Could this be a problem?

When attempting to debug with comgt I get the following output (and yes, the SIM card has been inserted :-) ):

root@OpenWrt:~# gcom -d /dev/ttyUSB0
 ***SIM ERROR***
Check device port configuration.
Check SIM is inserted
Test SIM in a mobile phone?
root@OpenWrt:~# gcom -d /dev/ttyUSB1
comgt 14:41:06 -> -- Error Report --
comgt 14:41:06 -> ---->                       ^
comgt 14:41:06 -> Error @74, line 4, Could not write to COM device. (1)

The output of dmesg and logread can be found here: https://gist.github.com/Jegp/9916097

Thanks in advance! :-)

(Last edited by jegp on 1 Apr 2014, 16:21)

Hi jepg,

I've got almost the same setup. My router is a TL-MR3040 and the Huawei E353 is a different version judging from the USB vendor/product IDs (12d1:14fe -> 12d1:1506). I get ttyUSB0, 1 and 2. Comgt -d /dev/ttyUSB0 shows that the E353 is registered.

Why would you want to load drivers manually if it works as-is?

I don't want to hijack your thread, but I've been unable to get extroot to work properly from an SD card inside the E353. OpenWrt boots, but I end up with a read-only file system. The problem with both the TL-MR3020 and MR3040 is that they need more flash memory to be really useful, and an external USB hub defeats the purpose of the battery-equipped MR3040.

(Last edited by epollari on 8 Apr 2014, 14:07)

I have a working 3g dongle setup, with a huawei e3131-s2 modem.

Try to use this guide, http://www.it-slav.net/blogs/2010/06/12 … n-openwrt/

Good question :-) But the problem was that after the modeswitch, only one of the interface had been assigned a driver, so I had to manually assign the option driver.
But.. It turns out that I 1) did not unlock the device (thanks to @slippern for his link on how to unlock Huawei modems!) and that I 2) used the wrong product id for modeswitching; instead of 12d1:1f01 -> 12d1:14db it was 12d1:1f01 -> 12d1:1001. Quite confusing :-) After the correct modeswitch four interfaces were identified and generic drivers were attached to them all. Are there any easy way to figure out these id's and message-contents?

Thanks for your help guys! Much appreciated. Now it's on to the actual work

PS.: I'll post the install scripts for the router (along with the usb_modeswitch configs) when I get everything up and running here: https://github.com/Jegp/DemTech-openwrt-setup

@epollari: I am afraid I haven't had any experience with SD-cards on the devices. I'm using a few large packages and I've managed to make it work by installing them in the ram. opkg -d ram did the trick for me (the destination is defined in /etc/opkg.conf).

(Last edited by jegp on 15 Apr 2014, 13:06)