I have a GA-Z170X-UD3 with BIOS F6, an Intel i7-6700k and 16GB of G.SKILL Ripjaws V Series (2 x 8GB) 288-Pin SDRAM DDR4 3000 (PC4 24000) model F4-3000C15D-16GVR. I am using the integrated Intel video and BIOS settings are all at the defaults. I am using a Samsung 850 EVO 500GB SSD for my Operating Systems and a pair of Seagate 500GB 7200 RPM hard drives in RAID 1 mode for data. I plan to boot in MBR mode so I confirmed that the BIOS had “Windows 8/10 Features” = Other OS and “Storage Boot Option Control” = Legacy only. I set SATA Mode Selection to RAID.
I installed Windows 7 and everything worked fine. I wanted to install a second operating system so I installed a 3rd party MBR boot loader called “System Commander V9.04”. This utility replaces the Windows MBR with an enhanced MBR. I rebooted my system and after it passed post the system just hung with a black screen with the status LED on the motherboard displaying “AE - Boot to Legacy OS”. I went back into the BIOS and changed the SATA Mode Selection to AHCI and the system was then able to boot properly to the System Commander MBR without changing anything else.
I ran additional tests and was able to determine the following:
- “Other OS, Storage Boot Option Legacy only” mode is able to boot the Windows 7 MBR in both AHCI and RAID modes.
- These same options are able to boot the System Commander MBR in AHCI mode, but they are unable to boot the System Commander MBR in RAID mode.
- When in RAID mode I confirmed that my SSD is detected as a “Non–RAID disk”.
- I tried BIOS versions 2, 5, and 6.
- I also tried setting Windows 8/10 Features = "Windows 8/10" and CSM Support = "Enabled".
Is there a problem with the BIOS that prevents the GA-Z170X-UD3 from loading 3rd party MBRs in RAID mode? I have an older Gigabyte GA-X38-DQ6 motherboard with an integrated Intel ICH9R RAID controller and it has no problems booting the System Commander MBR in RAID mode.
