How to restore access to ASUS WL-500gP v1 router with OpenWRT in FailSafe mode?

Question

ASUS

Hello!
I installed an OpenWRT system on an old ASUS WL-500gP v1 router ( wiki.openwrt.org/toh/asus/wl500gp ). I did everything, everything worked out, I immediately set up SSH access by key, looked at what was there. But then foolishly turned on DHCP in the settings via the web face (LuCI), since then I can not access the router.
Did this and that . Actually, it seems to enter failsafe mode (the power indicator flashes quickly), but it doesn’t enter telnet 192.168. 255.0), plugged the patch cord into LAN1 on the router). Maybe missed something?
Picked the Internet in search of an answer, but did not find anything similar even with other routers.
The router does not seem to look like a brick yet, and somehow I don’t want to give up. :)

Answer 1

In general, it turned out to regain access by re-uploading the firmware via TFTP in the 'diag mode' mode. Thanks to efkot for the idea about LAN4!
Here is a short guide on what I did. Maybe someone will come in handy. But note that I couldn't telnet in failsafe mode! (Although it might be worth trying to connect via telnet using the IP of the router that I installed in my native firmware - see below - and via LAN4, but I followed the instructions on the site - it was said that in failsafe mode the router accepts connections on 192.168. 1.1 regardless of previous settings).
So what I did:
1. Disconnected the router.
2. Set IP [192.168.5.2], mask [255.255.255.0] on the computer. Gateway and DNS are not required. (I set these LAN parameters - 192.168.5.0/24 on my native firmware before I installed OpenWRT).
3. Turned on the router in 'diag mode' (see wiki.openwrt.org/toh/asus/wl500gp#oem_installation... )
4. Plugged the patch cord on the router in LAN4!
5. Executed tftp -i 192.168.5.1 PUT openwrt-brcm47xx-squashfs.trx (naturally, the path to the firmware file, as well as the firmware file itself, as well as the IP address of the router (see step 2), may be different).
6. Following the instructions from the office. site, waited for a message about the successful download of the firmware file, then waited for its installation (the power indicator went out when the firmware was installed, after installation it turned on).
7. Turned off the router, making sure that the power indicator lit up (just in case, I waited 6 minutes, as indicated on the site).
8. I already set IP 192.168.1.2 and mask 255.255.255.0 on my computer.
9. Turned on the router, waited for the download.
10. Plugged in a patch cord on the router in LAN1.
Everything is ready. Now you can go to the web interface 192.168.1.1/.

Answer 2

Sometimes throws lan in the opposite direction, try in lan4