Hello All,
I am experiencing several issues while using the Quectel RM520N-EU module and would appreciate your guidance in resolving them:
When I try to connect to the 5G network, it seems that the USB connection is is highly unreliable.
When I try to connect via a QMI script, the USB interface seems to be connecting and disconnecting.
I am using an M.2 to USB3 adapter and I have already tried different USB cables and different USB ports. I tried to use a different m.2 to usb3 adapter that I know and guarantee that is working, with the same quectel device, but the issue prevails.
The output from the QMI logs is:
couldn't create QmiDevice: Couldn't query file info: Error when getting information for file “/dev/cdc-wdm0”: No such file or directory.
The output of the dmesg log is:
[ 2048.985406] usb 1-1.1: new high-speed USB device number 14 using xhci_hcd
[ 2049.087332] usb 1-1.1: New USB device found, idVendor=2c7c, idProduct=0801, bcdDevice= 5.04
[ 2049.087364] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2049.087382] usb 1-1.1: Product: RM520N-EU
[ 2049.087396] usb 1-1.1: Manufacturer: Quectel
[ 2049.087409] usb 1-1.1: SerialNumber: 452cefa1
[ 2049.113493] option 1-1.1:1.0: GSM modem (1-port) converter detected
[ 2049.113825] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0
[ 2049.114146] option 1-1.1:1.1: GSM modem (1-port) converter detected
[ 2049.114390] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1
[ 2049.114777] option 1-1.1:1.2: GSM modem (1-port) converter detected
[ 2049.115009] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB2
[ 2049.115389] option 1-1.1:1.3: GSM modem (1-port) converter detected
[ 2049.115636] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB3
[ 2049.117847] qmi_wwan 1-1.1:1.4: cdc-wdm0: USB WDM device
[ 2049.118692] qmi_wwan 1-1.1:1.4 wwan0: register 'qmi_wwan' at usb-0000:01:00.0-1.1, WWAN/QMI device, 6e:e0:62:0b:d0:d0
[ 2103.443379] usb 1-1.1: USB disconnect, device number 14
[ 2103.444808] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 2103.444888] option 1-1.1:1.0: device disconnected
[ 2103.446224] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 2103.446317] option 1-1.1:1.1: device disconnected
[ 2103.448352] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 2103.448488] option 1-1.1:1.2: device disconnected
[ 2103.450385] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[ 2103.450489] option 1-1.1:1.3: device disconnected
[ 2103.453412] qmi_wwan 1-1.1:1.4 wwan0: unregister 'qmi_wwan' usb-0000:01:00.0-1.1, WWAN/QMI device
[ 2115.005469] usb 1-1.1: new high-speed USB device number 15 using xhci_hcd
[ 2115.108414] usb 1-1.1: New USB device found, idVendor=2c7c, idProduct=0801, bcdDevice= 5.04
[ 2115.108444] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2115.108460] usb 1-1.1: Product: RM520N-EU
[ 2115.108475] usb 1-1.1: Manufacturer: Quectel
[ 2115.108488] usb 1-1.1: SerialNumber: 452cefa1
[ 2115.133753] option 1-1.1:1.0: GSM modem (1-port) converter detected
[ 2115.134096] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0
[ 2115.134475] option 1-1.1:1.1: GSM modem (1-port) converter detected
[ 2115.134771] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1
[ 2115.135165] option 1-1.1:1.2: GSM modem (1-port) converter detected
[ 2115.135438] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB2
[ 2115.135814] option 1-1.1:1.3: GSM modem (1-port) converter detected
[ 2115.136082] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB3
[ 2115.138410] qmi_wwan 1-1.1:1.4: cdc-wdm0: USB WDM device
[ 2115.140046] qmi_wwan 1-1.1:1.4 wwan0: register 'qmi_wwan' at usb-0000:01:00.0-1.1, WWAN/QMI device, 3a:12:f0:c4:d5:ce
[ 2118.511822] usb 1-1.1: USB disconnect, device number 15
[ 2118.513739] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[ 2118.513846] option 1-1.1:1.0: device disconnected
[ 2118.515505] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[ 2118.515600] option 1-1.1:1.1: device disconnected
[ 2118.517958] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[ 2118.518058] option 1-1.1:1.2: device disconnected
[ 2118.519944] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[ 2118.520042] option 1-1.1:1.3: device disconnected
[ 2118.520571] qmi_wwan 1-1.1:1.4 wwan0: unregister 'qmi_wwan' usb-0000:01:00.0-1.1, WWAN/QMI device
[ 2134.533408] usb 1-1.1: new high-speed USB device number 16 using xhci_hcd
[ 2134.634952] usb 1-1.1: New USB device found, idVendor=2c7c, idProduct=0801, bcdDevice= 5.04
[ 2134.634977] usb 1-1.1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 2134.634986] usb 1-1.1: Product: RM520N-EU
[ 2134.634992] usb 1-1.1: Manufacturer: Quectel
[ 2134.634998] usb 1-1.1: SerialNumber: 452cefa1
[ 2134.660049] option 1-1.1:1.0: GSM modem (1-port) converter detected
[ 2134.660501] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB0
[ 2134.661012] option 1-1.1:1.1: GSM modem (1-port) converter detected
[ 2134.661763] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB1
[ 2134.662370] option 1-1.1:1.2: GSM modem (1-port) converter detected
[ 2134.662993] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB2
[ 2134.663522] option 1-1.1:1.3: GSM modem (1-port) converter detected
[ 2134.663903] usb 1-1.1: GSM modem (1-port) converter now attached to ttyUSB3
[ 2134.666733] qmi_wwan 1-1.1:1.4: cdc-wdm0: USB WDM device
[ 2134.667887] qmi_wwan 1-1.1:1.4 wwan0: register 'qmi_wwan' at usb-0000:01:00.0-1.1, WWAN/QMI device, ba:bd:f3:af:5a:2b
[ 2170.300432] usb 1-1.1: USB disconnect, device number 16
The QMI script I am using:
#!/bin/bash
_dev="/dev/cdc-wdm0"
_if=$(sudo qmicli -d $_dev -p -w)
_apn="internet"
sudo qmicli -d $_dev -p --dms-set-operating-mode=low-power
sleep 2
sudo qmicli -d $_dev -p --dms-set-operating-mode=online
sleep 2
sudo qmicli -d $_dev -p --wds-start-network="ip-type=4,apn=$_apn" --client-no-release-cid
sleep 2
sudo ip link set $_if down
echo 'Y' | sudo tee /sys/class/net/$_if/qmi/raw_ip
sudo ip link set $_if up
sudo udhcpc -q -f -i $_if
The OS Version which i am using is
PRETTY_NAME="Ubuntu 22.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
Kernel Version which i am using
5.15.0-1071-raspi #74-Ubuntu SMP PREEMPT Fri Jan 17 12:10:53 UTC 2025 aarch64
Thank You
