Linksys EA7500 v3 installation method

Hi
The TOH page says that EA7500v3 is supported, but doesn't have a Device page. EA7500v1 and v2 had device pages, though. I followed the OpenWRT firmware link and found a SYSUPGRADE image and a Linux Kernel image. I downloaded the SYSUPGRADE one and tried installing it through the Linksys web UI. It refused to install it because the model doesn't match.
Has anyone successfully installed OpenWrt on EA 7500v3? Or anyone else with a way forward?
Thanks
Saqib

https://git.openwrt.org/openwrt/openwrt/commit/?id=2fbffb3643b012e37c692e8c390b916b8ad20fe3, if you get a gateway error when trying to access the page, hit refresh a cpl of times.

note wifi's not working.

Thanks, Frollic. Looks like it has to be done using the serial port. I'll try this out in a few days.