Unable to Boot Win10 Install Drive With CSM Disabled

[JbstormburstADV]

Hello,

So I've had my motherboard for a while, and when I did my initial Windows install, I realized I still had CSM enabled, which meant the boot sequence in the end was at least thirty seconds from button press to the login screen. So I setup a USB 2.0 drive using Rufus as a UEFI installer for Windows 10, plugged it in, and disabled CSM. However, when I tried to boot up after I disabled CSM, I couldn't get any output from my iGPU and after hitting Q-Code 99, which is normal, it went to d6, then Ad, before it finally went to 6F after quite a while. Is there something going on that I'm not aware of? Do I need to RMA the board? If needed, my parts list is as follows;

Intel Core i5 6600K
ASU ROG Maximus VIII Extreme
Cryorig R1 Universal (three fans)
EVGA 220-PS-1000-V1
Intel 750 400 GB (2.5" form factor)
WD Black 5 TB

If anyone can help, it would be appreciated.very much.

[BVr77]

hi,
first of all you must have a Windows UEFI version
( look into your key you should have a bootmgr.efi file and an EFI folder
the usb key doesn't need a boot sequence, it's your asus bios that boot the usb key, simply select your key in uefi mod in boot option.
your HD must be in GPT format to instal Windows in UEFI mode.

and remember most of time the bug is between the chair and the keyboard 😉

[JbstormburstADV]

BVr77 wrote:
hi,
first of all you must have a Windows UEFI version
( look into your key you should have a bootmgr.efi file and an EFI folder
the usb key doesn't need a boot sequence, it's your asus bios that boot the usb key, simply select your key in uefi mod in boot option.
your HD must be in GPT format to instal Windows in UEFI mode.

and remember most of time the bug is between the chair and the keyboard 😉

Yes, except the thing is that I did just that. I made the USB UEFI-bootable using Rufus' option to create a GPT partition for UEFI booting, and I do have both bootmgr.efi and the EFI folder. It's not like I haven't done this before, especially considering my experience with Arch Linux installation. And you still should at least be able to reach POST if CSM is disabled, yet it simply doesn't in my case. So again, if anyone has something to contribute apart from asking if I made the USB EFI-compliant, then that would be most helpful.

[vorpalzier]

JbstormburstADV wrote:
Yes, except the thing is that I did just that. I made the USB UEFI-bootable using Rufus' option to create a GPT partition for UEFI booting, and I do have both bootmgr.efi and the EFI folder. It's not like I haven't done this before, especially considering my experience with Arch Linux installation. And you still should at least be able to reach POST if CSM is disabled, yet it simply doesn't in my case. So again, if anyone has something to contribute apart from asking if I made the USB EFI-compliant, then that would be most helpful.

So what does diskpart say when you run it? Make sure your windows is in GPT mods. For some reason during my install it installed windows in another format. I got a great web page that helped me. I have my bios set up and honestly after post I am looking about @ 5sec boot times https://technet.microsoft.com/en-us/library/dn336946.aspx

[AKBAAR]

check if your GPU or anything on your pci-e is UEFI compliant. else it wont boot

[jdj9]

There is an easy solution to this, if you have not already figured it out.

Check out this link from Microsoft, they explain how to convert to UEFI without needing to backup, format, install OS, etc etc.

https://docs.microsoft.com/en-us/windows/deployment/mbr-to-gpt

You can do it directly from Windows 10 environment, no need to boot from USB or anything.