Linksys EA8500

Hey Friends I want to install Openwrt in my Linksys EA8500 but this router does not allow me to install its old firmware 1.1.4 versions or version 1.1.3 etc. I need help how I can install OpenWrt.

[OpenWrt Wiki] Linksys EA8500

I try the older firmware method but it won't work now I'm try to use TFTP method thanks for the help.

The TFTP method is too difficult for me 1.1.4 firmware trick is good please help me where I can find working 1.1.4 or 1.1.3 firmware. All firmware available on the internet are not working.