Main issue 4G down after few hours. Below is the full story. I'll try to share as much information as possible
I have ZBT WE826 router with 4G from AliExpress. It came with some kind of firmware, probably some old flavor of OpenWRT. Issue at the beginning was that router works for few hours and after like 3-8 hours (very random) I'm left without 4G connection. Remote restart does not help and I have to go on site and do power cycle.
Later seller share some LEDE Reboot firmware from 2018, but it was even worse- reboot each 8 minutes, no randomness. I suspect it was some kind of script, but did not had enough technical knowledge to search for solution, as firmware was quite old (from 2018).
Gathered OpenWRT knowledge by reading posts, and other documentation.
So, I've decided to install latest official OpenWRT for my device (ZBT W826 T 16M factory image). Install was successful and router came to life. 4G was not working out of the box but I've set it up based on bits and bytes found on web. These two resources lead me to success: https://openwrt.org/docs/guide-user/network/wan/wwan/ethernetoverusb_cdc
Fibocom NL678-e module is used for 4G connection. It looks like counterfeit as serial number is 12345678 (something like that)
But anyway I was happy that I have latest stable version, up and running. 4G connection is working and I can use wired and Wifi connection to access internet.
Left my router online (basically no devices connected to it) to hang overnight and in the morning I've noticed 4G is not working again. Tried to send 'dial' command (AT+GTRNDIS=1,1) again with picocom via USB3 but it did not work. After a little investigation, I've found that '/dev/ttyUSB0' devices (0 to 3) are missing. My 4G modem is on USB0 and AT commands accepted on USB3. Remote reboot does not help, I have to do full power cycle to get 4G working again. But again, after few hours it's gone with the same symptoms.
I like form factor of the touter to hang on wall and good Wifi coverage, I wish to use it in my setup.
Maybe some tech gurus could suggest me what to search for?
root@OpenWrt:~# picocom /dev/ttyUSB3
picocom v3.1
port is : /dev/ttyUSB3
flowcontrol : none
baudrate is : 9600
parity is : none
databits are : 8
stopbits are : 1
escape is : C-a
local echo is : no
noinit is : no
noreset is : no
hangup is : no
nolock is : no
send_cmd is : sz -vv
receive_cmd is : rz -vv -E
imap is :
omap is :
emap is : crcrlf,delbs,
logfile is : none
initstring : none
exit_after is : not set
exit is : no
Type [C-a] [C-h] to see available commands
Terminal ready
AT+GTUSBMODE?
+GTUSBMODE: 18
OK
AT+GTUSBMODE=?
+GTUSBMODE: (17-24)
OK
Install and configure "watchcat" to handle the disconnects. You may need to use a custom script with it that resets the modem using one or another way. Search the forum for references.
Thank you AndrewZ, I've followed your advice and has been able to setup connection:
I've reinstalled firmware to begin from fresh start, installed all required packages for QMI, changed AT+GTUSBMODE to 17 and followed resource how to set connection in QMI mode.
I don't know what I've done wrong initially, but I've restarted setting up from beginning once-again and I've managed to gain connection via Lan and Wifi and within router. Installed WatchCat as suggested but removed all default configuration to see how stable router is. So far, leaving router online overnight- it still works without noticeable issues for 19 hours. Logs does not show any unexpected issues. Looks promising! Time will show...