Proto ATC Fails to Obtain IP After L850 Firmware Update

[zzzt27]

Hi, I'm encountering an issue after updating the firmware on my L850 modem. Here are the details:

Modem: L850

• Previous Firmware: 18500.5001.00.01.17.64 (Build date: ~Jan 2018)
  Status: Worked fine with proto ATC

• Updated Firmware: 18500.5001.00.05.27.12 (Build date: Apr 23 2021, 16:08:59)
  Issue: Proto ATC no longer obtains an IP address

Unfortunately, I didn’t back up the previous firmware, so rolling back isn’t an option.

Is there any known fix or workaround for this issue? Do I need to adjust any additional settings for proto ATC to work with the updated firmware?

Thanks in advance for your help!

[mrhaav]

Hi
Can you set "Activate AT debugging" to All, restart your interface and paste syslog?

BTW, how did you update your modem?

[zzzt27]

log

Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.427352] usb 1-2: New USB device found, idVendor=8087, idProduct=095a, bcdDevice= 3.33
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.433389] usb 1-2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.440476] usb 1-2: Product: MODEM + 2 CDC-ACM + 3 CDC-NCM + SS
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.446402] usb 1-2: Manufacturer: Intel Corp.
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.450805] usb 1-2: SerialNumber: 004999010640000
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.500218] cdc_acm 1-2:1.0: ttyACM1: USB ACM device
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.514449] cdc_acm 1-2:1.2: ttyACM2: USB ACM device
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.528800] cdc_acm 1-2:1.4: ttyACM3: USB ACM device
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.576516] cdc_ncm 1-2:1.6: MAC-Address: 00:00:11:12:13:14
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.578272] cdc_ncm 1-2:1.6: setting rx_max = 16384
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.588778] cdc_ncm 1-2:1.6 eth2: register 'cdc_ncm' at usb-xhci-hcd.3.auto-2, CDC NCM (NO ZLP), 00:00:11:12:13:14
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.640248] cdc_ncm 1-2:1.8: MAC-Address: 00:00:11:12:13:16
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.641893] cdc_ncm 1-2:1.8: setting rx_max = 16384
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.652475] cdc_ncm 1-2:1.8 eth3: register 'cdc_ncm' at usb-xhci-hcd.3.auto-2, CDC NCM (NO ZLP), 00:00:11:12:13:16
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.704100] cdc_ncm 1-2:1.10: MAC-Address: 00:00:11:12:13:18
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.705707] cdc_ncm 1-2:1.10: setting rx_max = 16384
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.716675] cdc_ncm 1-2:1.10 eth4: register 'cdc_ncm' at usb-xhci-hcd.3.auto-2, CDC NCM (NO ZLP), 00:00:11:12:13:18
Sun Feb 23 20:39:57 2025 daemon.info dnsmasq-dhcp[1]: DHCPREQUEST(br-lan) 10.10.10.241 82:5e:e7:45:e3:f6
Sun Feb 23 20:39:57 2025 daemon.info dnsmasq-dhcp[1]: DHCPACK(br-lan) 10.10.10.241 82:5e:e7:45:e3:f6
Sun Feb 23 20:39:57 2025 daemon.warn odhcpd[2157]: No default route present, overriding ra_lifetime to 0!
Sun Feb 23 20:39:58 2025 daemon.warn dnsmasq[1]: possible DNS-rebind attack detected: dns.msftncsi.com
Sun Feb 23 20:39:59 2025 daemon.warn odhcpd[2157]: No default route present, overriding ra_lifetime to 0!
Sun Feb 23 20:40:01 2025 daemon.err uhttpd[2302]: [info] luci: accepted login on /admin/status/logs for root from 10.10.10.12
Sun Feb 23 20:40:11 2025 daemon.warn odhcpd[2157]: No default route present, overriding ra_lifetime to 0!
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Timeout running AT-command; AT+CGEREP=2,1
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Can't open device /dev/ttyACM0.
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Can't open device /dev/ttyACM0.
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Can't open device /dev/ttyACM0.
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Can't open device /dev/ttyACM0.
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Activate modem
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): Can't open device /dev/ttyACM0.
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (2557): ./atc.sh: eval: line 267: can't open /dev/ttyACM0: no such file
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9218): l850 is disconnected
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9218): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "l850" } (Permission denied)
Sun Feb 23 20:40:12 2025 daemon.notice netifd: Interface 'l850' is now down
Sun Feb 23 20:40:12 2025 daemon.notice netifd: Interface 'l850' is setting up now
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9227): ls: /..//net//address: No such file or directory
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9227): No interface could be found
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9241): l850 is disconnected
Sun Feb 23 20:40:12 2025 daemon.notice netifd: l850 (9241): Command failed: ubus call network.interface notify_proto { "action": 0, "link-up": false, "keep": false, "interface": "l850" } (Permission denied)
Sun Feb 23 20:40:12 2025 daemon.notice netifd: Interface 'l850' is now down

Let me know if you need any additional logs.

For the firmware update, I followed the steps from this guide:
https://radenku.com/upgrade-firmware-fibocom-l850-gl-l860-gl/

Additionally, I’ve tried switching the modem device from /dev/ttyACM0 to /dev/ttyACM2, but the result remains the same.

Let me know if there’s anything else I should check.

Thanks!

[mrhaav]

It looks like you don´t have /dev/ttyACM0 anymore.

Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.500218] cdc_acm 1-2:1.0: ttyACM1: USB ACM device
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.514449] cdc_acm 1-2:1.2: ttyACM2: USB ACM device
Sun Feb 23 20:39:55 2025 kern.info kernel: [ 47.528800] cdc_acm 1-2:1.4: ttyACM3: USB ACM device

Have you tried with /dev/ttyACM1 or /dev/ttyACM3?

[zzzt27]

I’ve tried switching the modem device from /dev/ttyACM0 to /dev/ttyACM2, but the result remains the same.

[zzzt27]

after i change /dev/ttyACMx then restart interface

Sun Feb 23 21:07:15 2025 daemon.notice netifd: Interface 'l850' is setting up now
Sun Feb 23 21:07:15 2025 daemon.notice netifd: l850 (3393): Initiate modem with interface eth2
Sun Feb 23 21:07:17 2025 daemon.notice netifd: l850 (3393): SIMcard ready
Sun Feb 23 21:07:18 2025 daemon.notice netifd: l850 (3393): Configure modem
Sun Feb 23 21:07:25 2025 kern.info kernel: [ 1696.880161] usb 1-2: USB disconnect, device number 19

[mrhaav]

Did your modem just reboot?

Sun Feb 23 21:07:25 2025 kern.info kernel: [ 1696.880161] usb 1-2: USB disconnect, device number 19

What do you have if you run AT+GTUSBMODE=? ?

[zzzt27]

What do you have if you run AT+GTUSBMODE=? ?

AT+GTUSBMODE?
+GTUSBMODE: 0

after i try change fw
log stuck here

Sun Feb 23 21:39:11 2025 daemon.notice netifd: wan (6385): Initiate modem with interface eth2
Sun Feb 23 21:39:11 2025 daemon.warn odhcpd[2180]: No default route present, overriding ra_lifetime to 0!
Sun Feb 23 21:39:13 2025 daemon.notice netifd: wan (6385): SIMcard ready
Sun Feb 23 21:39:14 2025 daemon.notice netifd: wan (6385): Configure modem
Sun Feb 23 21:39:24 2025 daemon.notice netifd: wan (6385): Activate modem
Sun Feb 23 21:39:25 2025 daemon.notice netifd: wan (6385): +CGEV: ME CLASS B
Sun Feb 23 21:39:25 2025 daemon.notice netifd: wan (6385): OK

[mrhaav]

Maybe the modem need some time to find the correct carrier. So just wait for a few minutes.

[zzzt27]

Maybe the modem need some time to find the correct carrier. So just wait for a few minutes.

I have waited for around 5 minutes, but it still couldn’t obtain an IP address. Before the firmware update, it was able to get an IP almost instantly.

[mrhaav]

Keep your interface running.
Run
COMMAND='AT+CFUN?' gcom -d <your ACM device> -s /etc/gcom/at.gcom
COMMAND='AT+COPS?' gcom -d <your ACM device> -s /etc/gcom/at.gcom
Check the result in syslog.

[zzzt27]

Sun Feb 23 22:45:43 2025 daemon.notice netifd: l850 (24897): SIMcard ready
Sun Feb 23 22:45:44 2025 daemon.notice netifd: l850 (24897): Configure modem
Sun Feb 23 22:45:54 2025 daemon.notice netifd: l850 (24897): Activate modem
Sun Feb 23 22:45:55 2025 daemon.notice netifd: l850 (24897): +CGEV: ME CLASS B
Sun Feb 23 22:45:55 2025 daemon.notice netifd: l850 (24897): OK
Sun Feb 23 22:46:20 2025 daemon.notice netifd: l850 (24897): AT+CFUN?
Sun Feb 23 22:46:20 2025 daemon.notice netifd: l850 (24897): +CFUN: 1,0
Sun Feb 23 22:46:20 2025 daemon.notice netifd: l850 (24897): OK
Sun Feb 23 22:46:22 2025 daemon.notice netifd: l850 (24897): AT+COPS?
Sun Feb 23 22:46:22 2025 daemon.notice netifd: l850 (24897): +COPS: 2
Sun Feb 23 22:46:22 2025 daemon.notice netifd: l850 (24897): sh: 0: unknown operand
Sun Feb 23 22:46:22 2025 daemon.notice netifd: l850 (24897): sh: 2: unknown operand
Sun Feb 23 22:46:22 2025 daemon.notice netifd: l850 (24897): OK

[mrhaav]

Try
COMMAND='AT+COPS=0' gcom -d <your ACM device> -s /etc/gcom/at.gcom

[zzzt27]

Try COMMAND='AT+COPS=0' gcom -d <your ACM device> -s /etc/gcom/at.gcom

aww thanks, it's working now XD