EG25 USB Disconnect when trying to transfer a 5MB file

Technical Subjects
1

I’m using an EG25-G on a Raspberry Pi Zero W, with a USB Hub, so power is independent of the Pi.
I have a bunch of images of 5MB stored in an SD, and every 5 min I upload one of these images to Dropbox. This system was working very fine until a few days. I can connect to the system using the EG25, it does upload a proxy of the same images, around 100kb every 5 min, but when I try to upload the 5MB image it either resets the connection or the Pi crashes.
If I split the file in 1MB and send it one by one there is no problem.

From log/messages:

Jul 1 17:02:46 Pi kernel: [ 322.157057] usb 1-1.3: USB disconnect, device number 4
Jul 1 17:02:46 Pi kernel: [ 322.158047] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
Jul 1 17:02:46 Pi kernel: [ 322.158195] option 1-1.3:1.0: device disconnected
Jul 1 17:02:46 Pi kernel: [ 322.159218] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
Jul 1 17:02:46 Pi kernel: [ 322.159362] option 1-1.3:1.1: device disconnected
Jul 1 17:02:46 Pi kernel: [ 322.160328] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
Jul 1 17:02:46 Pi kernel: [ 322.160497] option 1-1.3:1.2: device disconnected
Jul 1 17:02:46 Pi kernel: [ 322.167912] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
Jul 1 17:02:46 Pi kernel: [ 322.168096] option 1-1.3:1.3: device disconnected
Jul 1 17:02:46 Pi kernel: [ 322.169491] qmi_wwan 1-1.3:1.4 wwan0: unregister ‘qmi_wwan’ usb-3f980000.usb-1.3, WWAN/QMI device
Jul 1 17:02:59 Pi kernel: [ 335.350080] usb 1-1.3: new high-speed USB device number 5 using dwc_otg
Jul 1 17:02:59 Pi kernel: [ 335.590160] usb 1-1.3: New USB device found, idVendor=2c7c, idProduct=0125, bcdDevice= 3.18
Jul 1 17:02:59 Pi kernel: [ 335.590197] usb 1-1.3: New USB device strings: Mfr=1, Product=2, SerialNumber=0
Jul 1 17:02:59 Pi kernel: [ 335.590217] usb 1-1.3: Product: EG25-G
Jul 1 17:02:59 Pi kernel: [ 335.590234] usb 1-1.3: Manufacturer: Quectel
Jul 1 17:02:59 Pi kernel: [ 335.591820] option 1-1.3:1.0: GSM modem (1-port) converter detected
Jul 1 17:02:59 Pi kernel: [ 335.592253] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB0
Jul 1 17:02:59 Pi kernel: [ 335.592966] option 1-1.3:1.1: GSM modem (1-port) converter detected
Jul 1 17:02:59 Pi kernel: [ 335.593536] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB1
Jul 1 17:02:59 Pi kernel: [ 335.594653] option 1-1.3:1.2: GSM modem (1-port) converter detected
Jul 1 17:02:59 Pi kernel: [ 335.595179] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB2
Jul 1 17:02:59 Pi kernel: [ 335.596035] option 1-1.3:1.3: GSM modem (1-port) converter detected
Jul 1 17:02:59 Pi kernel: [ 335.596519] usb 1-1.3: GSM modem (1-port) converter now attached to ttyUSB3
Jul 1 17:02:59 Pi kernel: [ 335.597926] qmi_wwan 1-1.3:1.4: cdc-wdm0: USB WDM device
Jul 1 17:02:59 Pi kernel: [ 335.599237] qmi_wwan 1-1.3:1.4 wwan0: register ‘qmi_wwan’ at usb-3f980000.usb-1.3, WWAN/QMI device, 2e:4f:e3:4b:xx:xx
Jul 1 17:02:59 Pi mtp-probe: checking bus 1, device 5: “/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3”
Jul 1 17:02:59 Pi mtp-probe: bus: 1, device: 5 was not an MTP device
Jul 1 17:02:59 Pi mtp-probe: checking bus 1, device 5: “/sys/devices/platform/soc/3f980000.usb/usb1/1-1/1-1.3”
Jul 1 17:02:59 Pi mtp-probe: bus: 1, device: 5 was not an MTP device

Versions:
EG25GGBR07A08M2G
QConnectManager_Linux_V1.6.1
qmi_wwan driver version = 5.15.76-v7+
Linux Pi 5.15.76-v7+ #1597 SMP Fri Nov 4 12:13:17 GMT 2022 armv7l GNU/Linux
Raspbian GNU/Linux 11 (bullseye)

Any ideas?

2

Looks like a power issue to me.
Try checking voltage a few times with AT+CBC
I would also check if the modem talks to the same eNB and sector as before.

3

Thanks for the quick reply @jfrog

I just loop an AT+CBC every 500ms and started a transfer.
I can see a drop in the voltage and it goes back to normal, but a second and a half later it disconnects for good:

2023-07-01 18:11:10,082 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:10,606 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:11,132 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:11,655 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:12,177 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:12,700 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:13,224 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:13,747 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:14,271 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:14,794 - INFO - gsm_power:111 - +CBC: 0,62,3805
2023-07-01 18:11:15,319 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:15,841 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:16,370 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:16,893 - INFO - gsm_power:111 - +CBC: 0,62,3803
2023-07-01 18:11:17,416 - INFO - gsm_power:111 - +CBC: 0,40,3707
2023-07-01 18:11:17,939 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:11:18,462 - INFO - gsm_power:111 - +CBC: 0,61,3799
2023-07-01 18:11:18,985 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:11:19,508 - INFO - gsm_power:111 - +CBC: 0,61,3800
2023-07-01 18:11:20,033 - INFO - gsm_power:111 - +CBC: 0,62,3806

dmesg:
[Sat Jul 1 18:11:19 2023] qmi_wwan 1-1.3:1.4: nonzero urb status received: -71
[Sat Jul 1 18:11:19 2023] qmi_wwan 1-1.3:1.4: wdm_int_callback - 0 bytes
[Sat Jul 1 18:11:19 2023] usb 1-1.3: USB disconnect, device number 4
[Sat Jul 1 18:11:19 2023] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[Sat Jul 1 18:11:19 2023] option 1-1.3:1.0: device disconnected
[Sat Jul 1 18:11:19 2023] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[Sat Jul 1 18:11:19 2023] option 1-1.3:1.1: device disconnected
[Sat Jul 1 18:11:19 2023] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[Sat Jul 1 18:11:19 2023] option 1-1.3:1.2: device disconnected
[Sat Jul 1 18:11:19 2023] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[Sat Jul 1 18:11:20 2023] option 1-1.3:1.3: device disconnected

4

Not sure how to get eNB and sector but I try with +QNWINFO:
2023-07-01 18:31:19,633 - INFO - gsm_power:123 - +QNWINFO: “FDD LTE”,“72410”,“LTE BAND 3”,1750
2023-07-01 18:31:20,157 - INFO - gsm_power:111 - +CBC: 0,62,3805
2023-07-01 18:31:20,681 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:31:21,203 - INFO - gsm_power:111 - +CBC: 0,62,3805
2023-07-01 18:31:21,732 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:31:21,737 - INFO - gsm_power:123 - +QNWINFO: “FDD LTE”,“72410”,“LTE BAND 3”,1750
2023-07-01 18:31:22,259 - INFO - gsm_power:111 - +CBC: 0,62,3807
2023-07-01 18:31:22,783 - INFO - gsm_power:111 - +CBC: 0,62,3804
2023-07-01 18:31:23,307 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:31:23,831 - INFO - gsm_power:111 - +CBC: 0,61,3799
2023-07-01 18:31:23,835 - INFO - gsm_power:123 - +QNWINFO: “FDD LTE”,“72410”,“LTE BAND 3”,1750
2023-07-01 18:31:24,358 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:31:24,879 - INFO - gsm_power:111 - +CBC: 0,61,3800
2023-07-01 18:31:25,400 - INFO - gsm_power:111 - +CBC: 0,8,3510
2023-07-01 18:35:30,546 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:35:31,069 - INFO - gsm_power:111 - +CBC: 0,62,3807
2023-07-01 18:35:31,594 - INFO - gsm_power:111 - +CBC: 0,63,3809
2023-07-01 18:35:32,117 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:35:32,641 - INFO - gsm_power:111 - +CBC: 0,63,3809
2023-07-01 18:35:32,646 - INFO - gsm_power:123 - +QNWINFO: “FDD LTE”,“72410”,“LTE BAND 3”,1750
2023-07-01 18:35:33,169 - INFO - gsm_power:111 - +CBC: 0,63,3809
2023-07-01 18:35:33,693 - INFO - gsm_power:111 - +CBC: 0,63,3809
2023-07-01 18:35:34,216 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:35:34,740 - INFO - gsm_power:111 - +CBC: 0,62,3806
2023-07-01 18:35:34,746 - INFO - gsm_power:123 - +QNWINFO: “FDD LTE”,“72410”,“LTE BAND 3”,1750
2023-07-01 18:35:35,268 - INFO - gsm_power:111 - +CBC: 0,63,3809
2023-07-01 18:35:35,796 - INFO - gsm_power:111 - +CBC: 0,62,3807
2023-07-01 18:35:36,320 - INFO - gsm_power:111 - +CBC: 0,63,3809

dmesg:
[Sat Jul 1 18:31:25 2023] qmi_wwan 1-1.3:1.4: nonzero urb status received: -71
[Sat Jul 1 18:31:25 2023] qmi_wwan 1-1.3:1.4: wdm_int_callback - 0 bytes
[Sat Jul 1 18:31:25 2023] usb 1-1.3: USB disconnect, device number 6
[Sat Jul 1 18:31:25 2023] option1 ttyUSB0: GSM modem (1-port) converter now disconnected from ttyUSB0
[Sat Jul 1 18:31:25 2023] option 1-1.3:1.0: device disconnected
[Sat Jul 1 18:31:25 2023] option1 ttyUSB1: GSM modem (1-port) converter now disconnected from ttyUSB1
[Sat Jul 1 18:31:25 2023] option 1-1.3:1.1: device disconnected
[Sat Jul 1 18:31:25 2023] option1 ttyUSB2: GSM modem (1-port) converter now disconnected from ttyUSB2
[Sat Jul 1 18:31:25 2023] option 1-1.3:1.2: device disconnected
[Sat Jul 1 18:31:25 2023] option1 ttyUSB3: GSM modem (1-port) converter now disconnected from ttyUSB3
[Sat Jul 1 18:31:25 2023] option 1-1.3:1.3: device disconnected

The drop was much bigger this time, stopped logging the CBC right away

5

Yeah, I guess you are correct about the power. I have a twin device, with the same specifications, when I try to transfer a file of the same size by LTE the voltage doesn’t drop on the CBC query. I need to verify that PSU. Thanks.

6

cellID is available through AT+QENG="servingcell"
The idea was to compare the current value with the old one, but my understanding you do not have any historical data available.

7

It is not only a PSU. Assuming you have some sort of USB to PCIe adapter, this adapter will normally have a voltage regulator that converts 5V input from USB port to typically 3.3-4.2V (or 3.8V in your case) consumed by a modem. This regulator could be a weak point too.

8

I designed the circuit, when I say PSU I meant to check the soldering. The circuit is a MP1584 regulated to output 3.6V, don’t know why is reading 3.8. It has a 100uF capacitor in the output, it may be loose, what lets the voltage oscillate when current is drawn.
The design works well because I have other boards running smoothly, as this one was until a few days ago.
For the time being I will try to split the images and send 100k or 200k at the time, I do have 5 min to upload 5MB anyway.
Thanks for the suggestions.

9

Before voltage drop:
+QENG: “servingcell”,“NOCONN”,“LTE”,“FDD”,724,10,DC5C517,18,1750,3,5,5,C552,-85,-7,-58,19,-

Afer:
+QENG: “servingcell”,“NOCONN”,“LTE”,“FDD”,724,10,DC5C517,18,1750,3,5,5,C552,-85,-8,-57,14,-

Nice trick this AT+QENG=“servingcell”, not in the EC25&EC21 AT Commands Manual