Ive been having some issues as of late with my Strix z270e mobo, double booting into the BIOS on cold boots. This started recently after updating Win10 Pro to CU KB4549951. No modifications or major changes except this, in which this began immediately the next day after updating, verifying the update, shutting down normally (via start -> shutdown), switching off the PSU and disconnecting from my UPS.
The next day I plug everything back in, switch the power on at the PSU, power it on it starts for a second, then switches itself off, and turns itself back on about 2 seconds later. When it does this, the American Megatrends screen will appear and tell me to press F1 to enter setup. At this point, all of my BIOS settings need to be reentered and date/time are reset. I do nothing but save and exit, which will then load the OS. I then login to Windows, connect to the internet and date/time is automatically updated.
To test whether the CU might be at fault I uninstalled the CU, rebooted, shutdown normally and switched off the power at the PSU and disconnected from the UPS. Waited half an hour, reconnected to the UPS, switched on the power at the PSU and cold booted. Problem did not reoccur. Did this a few times in a 2 day period following to make certain. Reinstalled said CU to test again, problem returned immediately after. Naturally I uninstalled the CU again, rebooted and shut down normally. Performed 5 cold boot tests in the following 2 day period after 2nd uninstall and problem now remains. 5 out of 5 cold boots, reflected the same problem and it still ongoing. One thing to note however, this does not occur on restarts only on cold boots. A friend of mine who has the exact same parts/build down to the letter (even this same CU installed) is not seeing the same issue. Granted, he always has his PC connected to a power source, if this is relevant. Has anyone experienced this or have any ideas on how to resolve? My specs:
STRIX Z270e mobo
STRIX gtx 1080 GFX
Corsair RM750x Gold PSU
I7 7700k processor
2 8GB sticks (16 GB total) Corsair Vengeance RGB 3000 Mhz RAM
Samsung Evo 960 500 GB M.2 SSD
Western Digital 4 TB Black HDD
Corsair Hydro 100iv2 Cooler
Win10 Pro 1703
