I've got some Linksys E2500v3 at work. There is an openwrt firmware available and I tried to put OpenWRT on one of them.
Unfortunately only the WAN port is working with 19.07.7 for me. I recovered the linksys firmware with a UART cable.
I haven't gone far, but I've got the Linksys firmware bootlog and the OpenWrt bootlog.
Could you grant me access to the wiki, I can add this (bootlog, UART pinout, etc...) ?