Same struggle than you Bulli, so many issues on this product line. If one thing is stable this in my consumer grade 4G Huawei WAN :-(. Guys at Teltonika you should reflect on what you do want to achieve with the RUTX12 at this point...clients are not dump and will necessarily move away.
ri Aug 13 15:31:38 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:31:48 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:31:58 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:08 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:18 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:28 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:38 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:48 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:32:58 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:33:08 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:33:18 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:33:28 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
Fri Aug 13 15:33:38 2021 daemon.err ledman[4800]: Failed to find gsmd ubus object
AND well known one: over 40 times droped modem1 in 24 Hours....
[135437.297920] option1 ttyUSB4: GSM modem (1-port) converter now disconnected from ttyUSB4
[135437.301644] option 3-1:1.0: device disconnected
[135437.310259] option1 ttyUSB5: GSM modem (1-port) converter now disconnected from ttyUSB5
[135437.314415] option 3-1:1.1: device disconnected
[135437.322837] option1 ttyUSB6: GSM modem (1-port) converter now disconnected from ttyUSB6
[135437.327059] option 3-1:1.2: device disconnected
[135437.335465] option1 ttyUSB7: GSM modem (1-port) converter now disconnected from ttyUSB7
[135437.339780] option 3-1:1.3: device disconnected
[135437.456635] qmi_wwan 3-1:1.4 wwan1: unregister 'qmi_wwan' usb-xhci-hcd.1.auto-1, WWAN/QMI device
[135449.375686] usb 3-1: new high-speed USB device number 7 using xhci-hcd
[135449.563787] option 3-1:1.0: GSM modem (1-port) converter detected
[135449.564108] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB4
[135449.569723] option 3-1:1.1: GSM modem (1-port) converter detected
[135449.576160] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB5
[135449.582835] option 3-1:1.2: GSM modem (1-port) converter detected
[135449.589422] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB6
[135449.595726] option 3-1:1.3: GSM modem (1-port) converter detected
[135449.602129] usb 3-1: GSM modem (1-port) converter now attached to ttyUSB7
[135449.627264] qmi_wwan 3-1:1.4: cdc-wdm1: USB WDM device
I don't have easy critics but this starts to be enough. I'm on my second warranty replacement device and the second was actually worse than first.