Intel Motherboards : Z170M Extreme4 boot device issue

Author: parsec
Subject: Z170M Extreme4 boot device issue
Posted: 30 Jul 2016 at 10:54pm

Nunyerbusiness wrote: Guys, I have a Toshiba RD-400 SSD in the PCIe slot. I definitely had issues before with boot corruption using the Toshiba drivers. A perfectly stable, non-overclocked system would die and report 'no OS' on reboot, but just now I had the issue again without using their drivers. I went into UEFI simple, tried to set boot device to windows boot manager (RD400), but it would refuse to boot. I went into advanced and did the same thing, BOOM >> booted no problem. Anyone see ANY similar issues with other PCIe or m.2 drives?  I don't know if it was solved by mucking around in UEFI or it's drive hiccups.  I noticed it did happen immediately after I booted a USB to check my recovery was OK or not.  This fact makes it even stranger. ANY help or ideas to troubleshoot is greatly appreciated! (ps. that RD400 is a screamer)

What Windows version are you using?

I imagine you must have either CSM disabled, or the CSM option, Launch Storage OpROM Policy set to UEFI only, since you are using an NVMe SSD as the OS drive.

I have never used the Easy UEFI mode, but I wonder if the settings I mentioned above are preserved in Easy mode? Is the CSM option even available in Easy mode?

If you cleared the UEFI at any point, the CSM setting would be reset to its default, which normally will not allow you to boot from an NVMe SSD. I think ASRock may be setting CSM automatically now when a NMVe M.2 SSD is being used, but that may only be in Advanced mode.

If your OS boots from that SSD without running any type of repair on it, then there was no corruption of the boot record. The problem was simply the CSM option setting, apparently.