How to make active@boot disk bootable on uefi/gpt?

Hydranix said:

Also, if you are attempting to boot this flash drive in UEFI mode, you'll want to use FAT32

FAT32 applies to both UEFI BIOS and Legacy BIOS, right?

Hydranix said:

Have you tried actually booting the flash drive?

No. I want to use it to clean install Redstone 2 later.

Matthew Wai said:

FAT32 applies to both UEFI BIOS and Legacy BIOS, right?

Yes, that is correct. By using FAT32, you can boot in either Legacy mode, or UEFI mode if supported, and the flash drive contains both UEFI and Legacy boot files.

Matthew Wai said:

No. I want to use it to clean install Redstone 2 later.

Then I would suggest backing up the data on the drive and doing a full wipe to avoid any problems.

After the data has been backed up

Code:

diskpart
sel dis #
cle all
cre par pri
format fs=fat32 quick
act
ass letter=s
exit
bootsect /nt60 S: /force
bootsect /nt60 S: /force /mbr

copy over data and everything should work as expected

Hydranix said:

bootsect /nt60 S: /force
bootsect /nt60 S: /force /mbr

The above does not exist in post #7, so I did not run them. Why are they needed?
Before you wrote post #22, I had already done the following.
Is the USB drive bootable now?

I want to make a bootable USB drive to clean install the upcoming version of Windows 10.

Matthew Wai said:

I want to make a bootable USB drive to clean install the upcoming version of Windows 10.

This threads was originally concerning a UEFI-mode bootable flash drive. So I answered you under the assumption that you wanted to make a flash drive UEFI bootable.

Then you said:

Matthew Wai said:

FAT32 applies to both UEFI BIOS and Legacy BIOS, right?

So I added the extra bootsect commands which make the drive Legacy-mode bootable. So that you would have a flash drive which can do both.

I originally omitted the Legacy-mode steps because I've had many experiences of people mistakenly installing Windows on modern hardware in Legacy mode, and using the CSM (which slows down the boot process and places limitations on the OS to some degree) rather than in UEFI-mode, and since the IBM PC BIOS (aka Legacy BIOS) is entirely deprecated, I assume UEFI is what people want by default.

Matthew Wai said:

Is the USB drive bootable now?

In UEFI-mode it will boot if the contents of the Windows 10 ISO, not the ISO file itself, but what it contains, are copied to the flash drive.

If you want to also have the option to Legacy boot the flash (not recommended unless you know you need it to be) you will have to run the bootsect command to write the Legacy boot code to the flash drive. Of course the ISO contents will need to be copied to the flash drive as well, like I said above.


I hope I wasn't unclear, sorry if I over explain things a bit.

Hydranix said:

So I added the extra bootsect commands which make the drive Legacy-mode bootable.

No bootsect commands are needed in the method described in post #7, which applies to both UEFI and Legacy mode. Why are bootsect commands needed in my case?

I use an MBR disk, so I have to use the Legacy mode, but I might go over to GPT in the future.

Matthew Wai said:

No bootsect commands are needed in the method described in post #7, which applies to both UEFI and Legacy mode. Why are bootsect commands needed in my case?

I use an MBR disk, so I have to use the Legacy mode, but I might go over to GPT in the future.

the bootsect commands are unnecessary if not using Legacy mode. However, in your case, since you're using MBR partition table, and do not at this time want to move to a GPT, you'll need to use the bootsect commands on the flash drive.

I'd strongly advise, if your motherboard firmware is UEFI capable, to use a GPT formatted hard drive, and installing windows in UEFI mode, and disabling Legacy Emulation in your firmware (aka the Compatibility Support Module).

On MCT, should I select 'USB flash drive' or 'ISO file' for my bootable USB drive?

My ASUS motherboard supports UEFI, but my HDD is just 500 GB, so I don't see why I should use GPT, as I have been using MBR happily for years.