Netgear R7900 possibly bricked after flashing OpenWrt 21.02.3

My Netgear Nighthawk x6 R7900 router has been plagued by DNS issues of the OEM firmware for some time. I finally decided to try an open-source firmware, and downloaded OpenWrt from this page

I used the Netgear web GUI and flashed the openwrt.chk file, but then I am no longer able to connect to the router.

The router only has a single power LED on in red. If I connect my laptop to the LAN port, the LED of the port is led in white, but my laptop (running Ubuntu 22.04) could not get IP address via DHCP. I manually set IP address, but I could not ssh to 192.168.1.1 or any other address in /24.

I tried pressing the reset button on the router, nothing changes no matter how long I press.

I read the failsafe wiki page, when turning on my router, my power LED never blinks. I don't know if it is in the failsafe state already, or bricked.

I was also trying to revert to the OEM firmware, but could not find any documentation on how to do this (given I could not see web GUI or ssh)

does anyone have similar issues? I am appreciated if you can help me fix this.

I don't know anything about that router but shouldn't your ip address be 192.168.1.0/24 range?

from reading this page: https://openwrt.org/docs/guide-user/network/openwrt_as_routerdevice

I was under the impression that the default gateway IP is 192.168.1.1 and the default allowed IP range is 1.x, not 0.x. Because the DHCP did not work, so I did not really know what was the correct default range.

I just tried to manually request IP from 192.168.0.x, and set router address to either 0.1 or 1.1, but neither allow me to ssh to the router.

The reason i mentioned that range was because in your original post you said "192.163.1.1".. Notice the 163 part.

sorry, that was a typo.

Was R7900's wan port connected to the lan port of ISP' router or modem? If it was, disconnect it and power cycle R7900. Then try to access R7900 via 192.168.1.1.

@rwl408, no, the uplink (WAN) is not connected.

I guess the router is busted like you said. I don't have experience with R7900 although I used to have a R7000 loaded with DD-Wrt (and recently converted a R6700 to R7000). It seems that you need the CFE TFTP + serial recovery method according to the OpenWrt R7900 Techdata. From my understanding, R7900 is a Costco's version of R8000 so you can ask Netgear or DD-Wrt (supports R8000) forums for how to recovery from a bricked R8000/R7900 too.

Edit - Found this link in my browser's bookmark:
How do I upload firmware to my NETGEAR router using a TFTP client on Microsoft Windows?