Hello, here are the quick facts:
Router: Archer AC1750 v5
In use since: 2019
OpenWrt Version used: 18.06
Everything was working fine till yesterday. I then wrote a cron script to turn off both WiFi radios at certain points in time. (something like uci set wireless ... uci commit; wifi;)
Tried it a couple of times manually and it was working as expected. Over night it should turn off WiFi. The C7 router is used as WiFi client to another router (for connecting wired devices via the other router's uplink). The next morning after switching off wifi for 8 hours, then automatically turning it on again, LAN ports weren't working anymore. Wifi was connected between the 2 routers as expected, but no LAN access to the Archer C7.
I found out that when I rebooted the C7 or did a /etc/init.d/network restart LAN would work for ~1-2 minutes, sometimes less.
Nothing in the logs.
Even resetting didn't help. I did a reset keeping the reset button pressed for 10 secs. WiFi was not configured, just a normal router. And again: LAN would disappear after a minute or two.
All tests were performed with ping by the way, from a linux machine connected via ethernet (also tried a windows laptop).
Next step: I installed the original firmware using TFTP. Everything seems to work OK. DHCP is working, ping is working via ethernet, so LAN seems ok. Even after 5-10 minutes. So it is not a hardware failure.
It must be software related, something to do with OpenWRT.
I flashed OpenWRT 21, the LEDs on the router are blinking, but I don't get a DHCP lease. And if I set the IP manually to 192.168.1.29 or anything, I still cannot ping 192.168.1.1
I tried it with OpenWRT 19, and 18, to no avail.
I always flash the original firmware first. Then use the WebGUI to switch to OpenWRT.
Does anybody have a clue what the problem is?