ASUS Gryphon Z87 - Boot order resets

MisterSkilly · April 15, 2015

Hi!
I've installed the most recent Windows 10 Preview on my PC as UEFI, and ever since it chooses that as the first device to boot from. I did change the order in my BIOS in EZ-Mode (boot order changable via drag&drop) and in Advanced Mode. Didn't fix my issue, everytime I reboot it switches back to Windows Boot Manager: P3(my win10 drive). Then I thought the problem may be that my Windows 8.1 64bit isn't UEFI yet, so I changed that. Set the first disk to boot from to Windows Boot Manager: my windows 8.1 drive. Still doesn't work.
I've tried to set it just to the disk (without the Windows Boot Manager:) in front, but that still switches back to Windows Boot Manager: win10 disk in first place.
Also, I do not have any "Choose your operation system" on either Windows. On Windows 8.1 in the msconfig boot section, I only see Windows 8.1 as a OS, and in Win10 Preview only Windows 10.

The only way for me to get into Windows 8.1 is to go into my BIOS and manually boot from my Windows 8.1 disk.

Both disks are GPT of course. (Win 8.1 could be MBR too, but my win10 disk is over 2TB big, thus I need GPT. Yes, I run windows 10 on a partition on my 4TB drive)

Could that be a bug with Windows 10 maybe? Or am I just too stupid?

TIA,
Skilly