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Mac5555 · ‎07-13-2017

My specs:

-MAXIMUS VIII Impact (running latest BIOS 3401)
-i5 6600K (OC'd to 4.4 at 1.35v)
-16GB DDR4 RAM (XMP profile)
-Intel 750 U.2 drive (running latest firmware 8EV101H0)
-Windows 10 64-bit (running latest version 1703, 15063.483)
-UEFI completely (CMS disabled, Secure Boot disabled, Fast Boot disabled)
-Installed Windows 10 64-bit via USB (formatted using Rufus) - partition scheme of GPT for UEFI (no MBR) and FAT32
-no SATA drives or external drives installed/attached
-OC is pretty basic/nothing fancy
-Windows 10 has "Turn on fast startup" disabled/unchecked

I've had this same setup for a while now, and it's never given me any trouble. However, ever since upgrading the BIOS to 3401, I run into this odd issue where it will automatically boot into BIOS (BIOS shows the Windows Boot partition as first and only boot in the boot order, so it know it's there). Hitting F10 to restart will automatically boot into Windows like normal. Annoying and curious, but it works.

Out of every 1 of maybe 10 times, WIndows will randomly fail to boot up at all. It will act like it's booting into Windows, then show the "Repairing startup", and say it can't automatically fix it. No amount of reboots/repairs/etc. will allow the BIOS to recognize that the Windows Boot partition is there (again, BIOS still shows the Windows Boot partition as first and only boot in the boot order). To easily bypass this, I boot into my same Windows install USB, click "Repair this computer", and then select the Boot into Windows as Normal option. The computer restarts, and Windows 10 boots up like normal. Then the whole ordeal starts over (cold booting brings me to the BIOS, restarting boots into Windows, then roughly 10 or so times later of cold boots it fails to boot into Windows entirely).

I've tried different reformatted several times, ISO images, different USB sticks, etc. - the above issues still persist. I never had this issue before with the previous BIOS firmware (can't recall which version it was). Please help!

Mac5555 · ‎07-16-2017

Anyone? Would it be because of the GPT partition? I formatted the Windows install USB as GPT (using Rufus).

AKBAAR · ‎07-16-2017

I wish i can help. because I have almost setup like urs. but i didnt install windows on U.2 i got it on samsung 850pro SSD

but I do have U.2 but for games

Try modding the BIOS to latest Modules for IRST and LAN BOOT ROM . from here
http://www.win-raid.com/t154f16-Tool-Guide-News-quot-UEFI-BIOS-Updater-quot-UBU.html

also try flashing latest INTEL ME Firmware.
http://www.win-raid.com/t596f39-Intel-Management-Engine-Drivers-Firmware-amp-System-Tools.html

Mac5555 · ‎07-16-2017

Thank you for the help! I'll give those a try. Again, this is all strange because I've had the exact same hardware, using the exact same OS, and everything worked fine before upgrading the BIOS to 3401. Putting blame on the BIOS firmware seems silly/unlikely, but I'm scratching my head at what else could possibly be the matter.

Today, the drive is now completely failing to boot. So booting into the Windows install USB and running Disk Part in CMD shows that both partition 0 and 1 are listed as RAW file systems (instead of NTFS). At this point, I'm not concerned about lost data (have what I need already backed up), I'm more concerned that this issue gets resolved.

EDIT:
I also just noticed they've posted an upcoming BIOS: https://rog.asus.com/forum/showthread.php?94479-Z170-Z270-ROG-and-ROG-Strix-UEFI-updates-for-hyper-t...

AKBAAR · ‎07-16-2017

nice link, I Already have modded my BIOS 3401 to BA microcode a while a go, and other things too.

Mac5555 · ‎07-18-2017

Nothing personal AKBAAR, but those links you've been posting look questionable at best, and warranty-voiding at worst. I think I'll take my chances and just wait for the new BIOS to drop.

Mac5555 · ‎07-21-2017

So I think I've figured out what the issue is.

I went back into BIOS and loaded optimized defaults, restarted, and then turned off some basic boot stuff (disabled Fast Boot and CSM, Secure Boot set to Other OS). Saved and restarted and installed Windows 10 just like normal on the Intel 750 drive. Then shut everything off. Did a cold boot, and bam. Everything boots up perfectly fine (yes, off the 750), and in fact boots faster than ever.

I'm completely puzzled. I hadn't changed anything or upgraded any firmware since these issues had started. And then I realized - loading optimized defaults cleared out any OC settings I had (which was a basic CPU OC to 4.4, voltage set to 1.35). But I had also enabled the XMP profile on my RAM.

I recalled reading that DRAM timings can screw with PCIe devices (which the 750 is). Intel also has an official statement on this. So now I'm trying to figure out how to keep using the XMP profile, but also not prevent the 750 from booting properly. I'm still unsure if this whole thing is entirely due to the DRAM timing or if the new 3504 BIOS will fix something that's broken with the 3401 BIOS.

Mac5555 · ‎07-26-2017

So slight update, I've been using a regular old SATA drive for testing, and it turns out I'm getting similar errors. Again, in either cases (booting from Intel 750 U.2 drive or 850 Evo SATA drive), the Boot section in BIOS shows only the Windows Boot Loader (on X drive). However, the issue starts up when I either simply enable XMP, or even do a mild OC on my CPU (again, i5-6600K) - I'm talking 4.4 GHz at 1.35v. As I had never had an issue with any of this previously (same hardware, same OC, just different BIOS). Which leads me to believe that it's not necessarily a motherboard/hardware issue, but a BIOS issue.

But I think this will be my last ASUS board for a while. I had other odd issues with my previous board (ASUS MAXIMUS V GENE), and had to actually RMA that one. Now this board/BIOS is acting up, and nobody on these forums really reads these posts or provides feedback/support.

Menthol · ‎07-26-2017

Mac5555,
Could you please list your memory kit
unstable memory, overclocked or timings miss configured can corrupt an OS faster than anything, if everything works at default settings than it is possibly your overclock, either CPU or memory settings, if you have not read the overclocking guide for Skylake please do, every CPU and memory kit does not always work together and memory overclocking, even XMP settings more than likely because your CPU, memory overclocking, even XMP may require additional tuning of voltages, VCCIO and VCSSA mostly

Mac5555 · ‎07-27-2017

Menthol wrote:
Mac5555,
Could you please list your memory kit
unstable memory, overclocked or timings miss configured can corrupt an OS faster than anything, if everything works at default settings than it is possibly your overclock, either CPU or memory settings, if you have not read the overclocking guide for Skylake please do, every CPU and memory kit does not always work together and memory overclocking, even XMP settings more than likely because your CPU, memory overclocking, even XMP may require additional tuning of voltages, VCCIO and VCSSA mostly

Thank you for the help Menthol!

My kit is the Corsair Vengeance LPX 16GB (2x8) DDR4 3000MHz (CMK16GX4M2B3000C15). I checked my motherboard's compatibility list, and it shows this particular kit as compatible. As for the CPU OC, I've simply been setting the CPU Core Ratio limit to 44 (all cores synced), and set cpu voltage on Manual Mode at 1.350. With that CPU OC, and XMP enabled, I only encounter issues at cold bootup. Once I'm in Windows, I've had many long gaming sessions where everything runs stable/fine, using a variety of games.

MAXIMUS VIII Impact - Failing to boot to Windows (U.2 drive and UEFI/GPT)