You should be able to flash the new BIOS using a USB stick from the BIOS screen with your 6850k installed.

ValkyrieStar
 
 
If the CPU is not supported by the BIOS that comes with the board when it arrives, if you register the board here then submit a support ticket, they will send you a replacement BIOS with the updated version free of charge.

Wow, the BIOS chip is mounted in a socket? How cool is that! My CMOS chips are hard soldered and when I botched a flash on my 'A' BIOS I had to RMA the whole board. I wish  manufacturers were more thoughtful of their customer's down time and started installing these ICs in a socket too.

ValkyrieStar
All of my motherboards (maybe its just me buying the highest end one each time) have had socketed BIOS chips, though I dont think theres ever been a time where ive needed to test their support to see if theyll send a replacement haha.

I currently use the X99 Micro 2, and in my spare pc there's an Asus P8Q77-M with my old 3770K and DDR3 ram, oddly that thing has 2 bios chips, not sure which does what, one might be for raid setup info or something.

I was told by MSI that my second BIOS is useful for recovering a bad flash on the primary BIOS. I tried flashing my BIOS using the MSI Updater software from inside Windows and that is where I went wrong. Flashing a BIOS from Windows when using a RAID-0 array is a sure fire way to brick the BIOS as the process isn't finished when it restarts and when it reboots it sets the SATA ports to the default AHCI and it can no longer run the software to finish the flash. My original intention was to have my 'A' BIOS all stock clocks and default settings except for the XMP profile and use the 'B' BIOS for some seriously high overclock on my CPU for running benchmarks but whenever I switched the BIOS from A to B I had to reactivate Windows. IDK why Windows thought I had made a major hardware change but it did.

EVGATech_RayH
The EVGA FTW K comes with the Broadwell-E UEFI when shipped, BIOS v2.01, so the BIOS chip should not be necessary.

The FTW K I received a couple days ago has BIOS v2.00. Running stress tests and testing RAM has been flawless (G.Skill Trident Z 3200), there's no need for me worry about BIOS flash or switching to find out.
 
Unless the dual BIOS contains v2.00 and v2.01, all X99 FTW K boards may not have shipped with BIOS v2.01.

Im using the 6850K with the X99 FTW-K motherboard. It worked straight out the box for me. 

Method320
My 6800k worked out of the box, but the board shipped with 2.00 bios, and I needed to update to 2.01 in order to get stable overclocks.

How could you update your bios that doesnt support 6850k via unsupported 6850k installed?

Same problem here EVGA X99 FTW-K  mobo  does not work out of the box with the 6850K processor and Im on my 3rd RMA MB and 2nd 6850k chip with the same results. I had to go buy ASUS 2011v3 socket MB to be sure that it wasnt a bad cpu and sure enough dropped the processor in the ASUS board it fired right up . If you do need a bios update change Ive never had to do that out of the package and you cant do it if the cpu doesnt post and I am waiting for my new updated bios. EVGA techs keep claiming that theres success storys with that board & 6850K chip there is one guy  that it worked for out of the box thats an awful % rating DO NOT BUY THIS BOARD AS A CONSUMER YOU SHOULD NOT HAVE TO FIX THERE PROBLEMS. They need to change thier policy if the board doesnt work for  you need to get your money back and I think they need to stay out of the business of motherboards and stick with what thier best at video cards & power supplys.
 

EVGA sent me the new updated bios chip and I changed out the bios chip and it fired right up and your running almost the exact same parts setup as me my question is did you have windows 10 installed when you booted up your new motherboard that would explain why your MOBO booted up I was trying to get it to post without a HD & the power would just flux off and on over and over if you didnt you were one of the lucky ones but it was a really easy fix once you knew what the problem was. EVGA will send you the new bio chip @ no cost just take great care when changing out the bio chip watch a demo on youtube if your not sure about something. I also had some other ideas if the new bios chip didnt work I had a running EVGA X79 socket 2011 i was going to pull the bios out of that HD I think they run the same bios update or download windows 10 on the Samsung 850 HD with the newer 2.03 update with the X79 socket 2011 MB but the new bios chip that I changed out worked. People can buy that EVGA X99 FTWK MB but your taking a chance just make sure the bios are updated on your new MB depending on the processor your using the socket 2011v3 had a limited selection of I7 processors I think about 6 or 7 version ranging from 4 core to 10 core do not run this socket if on a budget as the cheapest I7 for the 2011v3 socket is up around $400 depending on supply & demand and the 10 core I7 are as high as $1600. EVGA said the older 6 core 5850K 2011 socket works with the older bios and the older socket 2011 MB have really come down in price I went with the 6850K because it is multi pci express lane ready processor as the 5850 are not and Im using 2 X 1070 GTX FTW + 1 X 670 GTX FTW physx but for sure the 6800 & up does not at least for me it didnt good luck with your setup Im looking to run VR with this build.
Intel Core i7-6850K Broadwell-E 6-Core 
Corsair Hydro Series H110i Extreme Performance Water / Liquid CPU Cooler Cooling
EVGA X99 FTW K 2011-v3 Intel X99
CORSAIR Dominator Platinum 32GB (2 x 16GB) SDRAM DDR4 3000
1 X SAMSUNG 850 EVO 250GB
1X  SAMSUNG 850  EVO 500GB                                                                                                                                                               
2 X SLI -  EVGA GeForce GTX 1070 FTW
1 X Physx - EVGA GeForce GTX 670 FTW
EVGA SuperNOVA 1300 watt