Built-In Graphics on Asus Maximus-VI Formula not working apparently

I'm using maximux vi formula with dedicated gpu GTX-660. I tried to use built-in gpu (just for checking) of the board by changing settings in the BIOS but the screen remains blank while the system continues to work. Even removed gtx660 and try to use built-in gpu but result was same. processor is i7-4770.

What step I'm missing to use that gpu? Any help
 
In the bios, there should be a setting to select which graphics adapter should be used to display bios and startup messages.
If you have found and set this properly, and do not get a screen on the attached display, then a call to motherboard support might be in order.
The default is probably the discrete card if it is installed.
If the GTX660 is removed, you should, by default, see the bios messages on the integrated adapter.

Are you selecting the appropriate input on your monitor each time?
 
Using HDMI port. Monitor has HDMI/VGA ports. Formula has HDMI and display port. Yes I've manually set the Primary Adapter to iGPU. There are three options [Auto, PCIe, iGPU].
System working perfectly with discrete gpu but still no display on integrated one.
 
Guess what. After so much troubleshooting at the end the problem was with the HDMI cable. Plugged in HDMI cable shipped with my Sony DVD player and here it goes iGPU works. Gosh! I thought review on HDMI cables by CNET was considerable but my experience is different now. Anyhow thanks to all for their support.
 

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