GL-X750 AT Commands fail

Technical Support for Routers
1

Hello community,

I was attempting to setup a Verizon MVNO SIM in my Spitz this evening and ended up jacking up the modem configuration. Somehow I got the modem to show up under both 3G/4G modem and USB Tethering? Anyways I ended up factory resetting the device and the modem still shows up under USB Tethering. So I’m trying to wipe the modem configuration and when I issue the command (AT+QPRTPARA=3) I get an error message on /dev/ttyUSB0 or /dev/ttyUSB1 of “ERROR: Failed to Execute Command”

Hoping the community here has some ideas on how I can factory reset the modem?

2

Can you show me a screenshot of that? Never saw that it appear as tethering.

The interface for AT command is ttyUSB2, not ttyUSB0 or ttyUSB1

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3

When trying to run AT commands on the modem the only options I get are either ttyUSB0 or ttyUSB1. I have attached several screenshots via multiple posts.

Tethering
Tethering905×278 12.2 KB

Here is the list of AT commands that I ran that appeared to have caused this issue:

AT+QMBNCFG="AutoSel",0
AT+QMBNCFG="Deactivate"
AT+QCFG="usbnet",2
AT+QCFG="nwscanmode",3,1
AT+CGDCONT=1,"IPV4V6","VSBLINTERNET"
4

Tethering2
Tethering2768×383 29.9 KB

5

Modem_Manual_Setup
Modem_Manual_Setup1075×614 84.8 KB

6

AT_Commands
AT_Commands801×414 28.4 KB

7

Cannot believe it. Very strange.

8

Any suggestions on what I could do to fix the issue?

9

Just some more information about what happened. It appears I changed the configuration mode from QMI (Default) to ECM by issuing AT command “AT+QCFG=“usbnet”,1”. I cannot seem to figure out how to issue AT commands to the modem to set it back into QMI mode.

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10

From Quectel EC25 4G modem QMI mode - #3 by idarlund - Hardware Questions and Recommendations - OpenWrt Forum

AT+QCFG="usbnet",0 - is PPP & QMI (default)
AT+QCFG="usbnet",1 - is ECM.
AT+QCFG="usbnet",2 - is MBIM

Can you try?

11

I would love too, except I can’t seem to issue any AT commands to the modem. I even installed socat and try issuing the commands against ttyUSB2 and the device isn’t responsive.

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12

You didn’t mention your model so I tried my, XE300 with EP06ELAR03A08M4G.

Step 1: Changing to ECM mode.

I issued AT+QCFG="usbnet",1 and then did a modem reset from the UI, then the modme goes to ECM mode.

I still can see ttyUSB1 to ttyUSB3. This may be different from X750 because XE300 has 1 more ttyUSB.
I cannot connect in the modem section

image
image796×406 12.1 KB

I can usb0 in tethering section and I just click connect and it works.

image
image797×361 8.47 KB

Step 2: AT+QPRTPARA=3

I issued AT+QPRTPARA=3 and the modem respond OK. Then I did a modem reset. The status is still the same as in Step 2.

I think this command does not work at all. Maybe this is related to modem’s firmware version as well.

Step 3: AT+QCFG=“usbnet”,0

I issued AT+QCFG="usbnet",0 and got “OK”. Then did a modem reset from the UI.
The modem goes back to original mode.

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13

I have the GL-X750v2 with a EC25-AF modem. It won’t issue any commands on the modem I either get a busy message or another message I forget. Doesn’t matter if I try issuing the commands on ttyUSB1 or tryUSB2.

14

Then seems nothing could be done now.

15

So I assume you believe the modem is bricked and will need to be replaced?

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16

Yes. It may be just easier to replace the modem than indepth debrick.

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