Asus Deluxe Prime X299 won't update bios, not proper bios

[Ashton_Scott]

My motherboard has bios 3701 and I wanted to update it to 4201. I boot into the bios and start the EzFlash.  I navigate to the file.  I have named the file according to the manual and the recommendation with the renamed tool.  x299D2.cap and x299D.cap.  Either file when asked to read the file and error states that this is not the proper bios.  I've also tried with the next bios after 3701, 3801, and same issue.

Any suggestions?

[restsugavan]

Another easy way. Did you have trying ?

EZ Flash support both offline and online updates via BIOS menu . Choosing online instead . Take it easy 

[Ashton_Scott]

Thanks, I tried both Static Ip and DHCP for connection type and both failed connection.  I have now also tried the flashback feature on this motherboard and I believe it also considers the file to be wrong for this bios.  Any other Suggestions

[Rooke]

A couple of hours ago, I updated my wife's X299 with BIOS 4201, and had no problems with it. 
How did you extract the BIOS and Renamer files from the .zip?  
Sometimes just copying the files from the .zip file doesn't work properly using the File Explorer.
I used 7-Zip to extract them to a non-compressed work folder before using the renamer to change the "PRIME-X299-DELUXE-ASUS-4201.CAP" to "X299D.CAP". 
Then I copied the "X299D.CAP" file to a USB thumb drive that I used in the EZ Flash.

I know some people would argue about not having to use 7-Zip to do the extract, but it's worked flawlessly for me for over 10 years.  I stick with what works.