Just got my X99P-SLI board back from Gigabyte after the needed RMA BIOS F22 Broadwell-E fiasco and it now boots up and works with my 6900k CPU. I installed all of the newest drivers and utilities download from GB website but I get a Thunderbolt warning pop up even after running the FW update and rebooting. I already started another ticket with GB Support but was wondering if this issue is common. I don't have yet a USB-C to Thunderbolt 2 adaptor to test my peripheral to see if it works but the pop up warning makes me believe it will not. I will know today or tomorrow when my adaptor comes.