Greetings!
I recently dug up an old Asus RT-N15U that I have flashed OpenWRT on some years ago.
It seems to be starting at the default address 192.168.1.1 and on the login page I can see I am running OpenWrt 18.06.4 r7808-ef686b7292. I do not remember the credentials I have set for it though, so I can not login through web or ssh.
I tried the generic factory reset procedure described in the docs, but it doesn't work - holding the reset button for 10 seconds or more has no effect. I also tried invoking failsafe mode using either the reset or wpa button, but neither did work - the router is always booting in to regular operation.
Any ideas?
Did you release the WPS button immediately after the power led started flashing?
I did multiple attempts both pressing the button repeatedly or just once after the led starts flashing.
I also tried listening with tcpdump for the signalling udp package as described in the guide, on all ports, but never received any.
Eventually I ended up managing to invoke the Asus stock recovery mode by holding down the reset button while powering on and recovering to stock firmware with the Asus utility.
Still curious though, why neither openwrt's factory reset nor failsafe mode were working, while the router itself was operating.
That's normally how it's done with most major brands of WiFi home routers. I would document your process. I prefer to use a flashing utility vs the GUI for safety.