A problem with the LTE modem on TL-MR6400 v7 router

Installing and Using OpenWrt Network and Wireless Configuration
1

Several days ago I installed the OpenWRT on my TL-MR6400 v7 router (I installed version 23.05.5. Although it supports MR6400 v5, OpenWRT seems to work nicely on my V7, and the modem is the same Quectel EC25).

I installed everything as suggested on the forum regarding the QMI interface, including the mrhaav's uqmi package, but I have a problem.

My LTE card gets its normal IP address from the network, but after several seconds disconnects and usually ends up with an error IPV4_APN_ERROR. Apn is correctly set, and the PDP type is set to IPV4/IPV6. What else can be the issue?

2

Hi
Can you past your syslog where the modem connects and disconnects?

3

Hello! Here are the lines from the log file with my comments:

#This is when it shows the IPV4_APN_ERROR

Wed Dec  4 06:55:38 2024 daemon.notice netifd: Interface 'wwan2' is setting up now
Wed Dec  4 06:55:49 2024 daemon.notice netifd: wwan2 (16475): PINcode disabled
Wed Dec  4 06:55:49 2024 daemon.notice netifd: wwan2 (16475): Data format set to raw-ip
Wed Dec  4 06:55:49 2024 daemon.notice netifd: wwan2 (16475): Default profile: 1
Wed Dec  4 06:55:49 2024 daemon.notice netifd: wwan2 (16475):  registered on 21805
Wed Dec  4 06:55:50 2024 daemon.notice netifd: wwan2 (16475): Registered to m:tel on WCDMA
Wed Dec  4 06:55:51 2024 daemon.notice netifd: wwan2 (16475): Unable to connect with ipv4, check APN settings
Wed Dec  4 06:55:51 2024 daemon.notice netifd: wwan2 (16539): Stopping network wwan2
Wed Dec  4 06:55:51 2024 daemon.notice netifd: wwan2 (16539): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wwan2" } (Permission denied)
Wed Dec  4 06:55:51 2024 daemon.notice netifd: Interface 'wwan2' is now down
Wed Dec  4 06:55:52 2024 daemon.warn odhcpd[1365]: No default route present, overriding ra_lifetime!

#I restarted the interface without changing anything, and here it connects for several seconds getting the correct IP addres, and then again shows the IPV4_APN_ERROR

Wed Dec  4 06:59:51 2024 daemon.notice netifd: Interface 'wwan2' is setting up now
Wed Dec  4 07:00:02 2024 daemon.notice netifd: wwan2 (17111): PINcode disabled
Wed Dec  4 07:00:02 2024 daemon.notice netifd: wwan2 (17111): Data format set to raw-ip
Wed Dec  4 07:00:02 2024 daemon.notice netifd: wwan2 (17111): Default profile: 1
Wed Dec  4 07:00:03 2024 daemon.notice netifd: wwan2 (17111):  registered on 21805
Wed Dec  4 07:00:03 2024 daemon.notice netifd: wwan2 (17111): Registered to m:tel on WCDMA
Wed Dec  4 07:00:05 2024 daemon.notice netifd: wwan2 (17111): Connected with IPv4
Wed Dec  4 07:00:06 2024 daemon.notice netifd: wwan2 (17111): Unable to connect with IPv6
Wed Dec  4 07:00:06 2024 daemon.notice netifd: wwan2 (17111): Setting up wwan0
Wed Dec  4 07:00:06 2024 daemon.notice netifd: Interface 'wwan2' is now up
Wed Dec  4 07:00:06 2024 kern.info kernel: [68293.633241] device wwan0 entered promiscuous mode
Wed Dec  4 07:00:06 2024 daemon.notice netifd: Network device 'wwan0' link is up
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: reading /tmp/resolv.conf.d/resolv.conf.auto
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using nameserver 81.93.64.11#53
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using nameserver 81.93.64.3#53
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for test
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for onion
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for localhost
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for local
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for invalid
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for bind
Wed Dec  4 07:00:07 2024 daemon.info dnsmasq[1]: using only locally-known addresses for lan
Wed Dec  4 07:00:07 2024 daemon.warn odhcpd[1365]: No default route present, overriding ra_lifetime!
Wed Dec  4 07:00:08 2024 user.notice firewall: Reloading firewall due to ifup of wwan2 (wwan0)
Wed Dec  4 07:00:08 2024 user.notice uqmi_d: Daemon started
Wed Dec  4 07:00:11 2024 user.notice firewall: Reloading firewall due to ifupdate of wwan2 (wwan0)
Wed Dec  4 07:00:39 2024 user.notice uqmi_d: Modem disconnected
Wed Dec  4 07:00:39 2024 daemon.notice netifd: Interface 'wwan2' has lost the connection
Wed Dec  4 07:00:39 2024 kern.info kernel: [68326.932503] device wwan0 left promiscuous mode
Wed Dec  4 07:00:39 2024 daemon.warn dnsmasq[1]: no servers found in /tmp/resolv.conf.d/resolv.conf.auto, will retry
Wed Dec  4 07:00:39 2024 daemon.notice netifd: Network device 'wwan0' link is down
Wed Dec  4 07:00:40 2024 user.notice uqmi_d: Unable to re-connect IPv4 - Interface restarted
Wed Dec  4 07:00:40 2024 daemon.notice netifd: wwan2 (17427): Stopping network wwan2
Wed Dec  4 07:00:40 2024 daemon.notice netifd: wwan2 (17427): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wwan2" } (Permission denied)
Wed Dec  4 07:00:40 2024 daemon.notice netifd: Interface 'wwan2' is now down
Wed Dec  4 07:00:40 2024 daemon.notice netifd: Interface 'wwan2' is setting up now
Wed Dec  4 07:00:51 2024 daemon.notice netifd: wwan2 (17511): PINcode disabled
Wed Dec  4 07:00:51 2024 daemon.notice netifd: wwan2 (17511): Data format set to raw-ip
Wed Dec  4 07:00:51 2024 daemon.notice netifd: wwan2 (17511): Default profile: 1
Wed Dec  4 07:00:52 2024 daemon.notice netifd: wwan2 (17511):  registered on 21805
Wed Dec  4 07:00:52 2024 daemon.notice netifd: wwan2 (17511): Registered to m:tel on WCDMA
Wed Dec  4 07:00:53 2024 daemon.notice netifd: wwan2 (17511): Unable to connect with ipv4, check APN settings
Wed Dec  4 07:00:53 2024 daemon.notice netifd: wwan2 (17658): Stopping network wwan2
Wed Dec  4 07:00:53 2024 daemon.notice netifd: wwan2 (17658): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wwan2" } (Permission denied)
Wed Dec  4 07:00:53 2024 daemon.notice netifd: Interface 'wwan2' is now down
4

how many wwan* have you got ?

5

wwan2 is for lte modem, wwan0 is wifi.

6

Update the modem firmware if you can, disable MBN autoselection as shown here Registration denied on Lebara Sim - #7 by AndrewZ
switch the modem to MBIM and follow https://openwrt.org/docs/guide-user/network/wan/wwan/ltedongle

7

You can turn off the uqmi_daemon with:

uci set network.wwan2.daemon=false
uci commit network

and restart the interface.

For some unknown reason the daemon thinks the session is down.

8

OK. Now I have to tell more about my problem. I actually have two of these routers, and I want to establish a route over their LTE cards so that hosts connected to routers can communicate to each other. Is such routing even possible over LTE?

The reason I am asking this: At one moment, I somehow made these LTE cards working in the OpenWrt environment on both router in QMI mode, and I could ping both of them from routers and PCs connected to these routers. But when I made the simple static routes to make PCs communicate to each other, that didn't work.

While trying to solve this problem, I somehow made one, then both of my modems behave erratically in QMI mode, and that brought me to ask this question.

Now I have the strange situation in MBIM mode. One LTE card seems to be working, has its IP address, and the one in the other router reports the PIN code rejected error, although there is no PIN on it (checked with AT+CPIN? also).

Here is the log dump from this modem. Strangely, there is no message regarding PIN code in log.

Mon Dec  2 18:01:26 2024 daemon.notice netifd: wwan9 (6517): mbim[6517] Stopping network
Mon Dec  2 18:01:26 2024 daemon.notice netifd: wwan9 (6517): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wwan9" } (Permission denied)
Mon Dec  2 18:01:26 2024 daemon.notice netifd: Interface 'wwan9' is now down
Mon Dec  2 18:01:26 2024 daemon.notice netifd: Interface 'wwan9' is setting up now
Mon Dec  2 18:01:26 2024 daemon.notice netifd: wwan9 (6526): mbim[6526] Reading capabilities
Mon Dec  2 18:01:27 2024 daemon.warn odhcpd[1372]: No default route present, overriding ra_lifetime!
Mon Dec  2 18:01:41 2024 daemon.notice netifd: wwan9 (6526): ERROR: mbim message timeout
Mon Dec  2 18:01:41 2024 daemon.notice netifd: wwan9 (6526): mbim[6526] Failed to read modem caps
Mon Dec  2 18:01:56 2024 daemon.notice netifd: wwan9 (6526): ERROR: mbim message timeout
Mon Dec  2 18:01:56 2024 user.notice root: mbim bringup failed, retry in 15s
Mon Dec  2 18:02:11 2024 daemon.notice netifd: wwan9 (6624): mbim[6624] Stopping network
Mon Dec  2 18:02:11 2024 daemon.notice netifd: wwan9 (6624): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "wwan9" } (Permission denied)
Mon Dec  2 18:02:11 2024 daemon.notice netifd: Interface 'wwan9' is now down
Mon Dec  2 18:02:11 2024 daemon.notice netifd: Interface 'wwan9' is setting up now
Mon Dec  2 18:02:11 2024 daemon.notice netifd: wwan9 (6632): mbim[6632] Reading capabilities
Mon Dec  2 18:02:12 2024 daemon.warn odhcpd[1372]: No default route present, overriding ra_lifetime!
Mon Dec  2 18:02:26 2024 daemon.notice netifd: wwan9 (6632): ERROR: mbim message timeout
Mon Dec  2 18:02:26 2024 daemon.notice netifd: wwan9 (6632): mbim[6632] Failed to read modem caps
Mon Dec  2 18:02:41 2024 daemon.notice netifd: wwan9 (6632): ERROR: mbim message timeout
Mon Dec  2 18:02:41 2024 user.notice root: mbim bringup failed, retry in 15s

I also noticed that in the router where LTE works, this wwan9 interface I made for modem has wwan0 as the device, and on the problem router its wwan9 interface has some mbim-wwan9 device.

9

The problem is solved. I forgot to initialize the other modem with the AT commands for MBIM mode, as stated in:
https://openwrt.org/docs/guide-user/network/wan/wwan/ltedongle

When I read several posts where people asked these questions, I kept asking myself why @AndrewZ kept asking them if they did everything from this manual. Now I know. :flushed:

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10

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