I used the EFI from the post to boot into USB installer. it loads everything up but just after 2 seconds of showing apple logo the screen goes blank. I have used DVI nad HDMI both but same problem. In the config.plist I added entries for my iGPU
<key>DeviceProperties</key>
<dict>
<key>Add</key>
<dict>
<key>PciRoot(0x0)/Pci(0x2,0x0)</key>
<dict>
<key>AAPL,ig-platform-id</key>
<data>BwCbPg==</data>
<key>framebuffer-patch-enable</key>
<string>01000000</string>
</dict>
<key>PciRoot(0x0)/Pci(0x1b,0x0)</key>
<dict>
<key>layout-id</key>
<data>AQAAAA==</data>
</dict>
</dict>
<key>Delete</key>
<dict/>
</dict>