How to create an EFI bootable Windows installer USB stick w/o Rufus ?

Megahertz said:

NovHak, You don't burn a iso to USB drive. You extract the iso to the USB drive Fat32 partition

In the case of Windows installer ISOs, I obviously agree because MS doesn't provide hybrid ISOs. However, there's a fair number of other OSes that provide installers as hybrid ISOs, Ubuntu being one of the most well known ones, where one can indeed just write the ISO to a USB stick raw device and boot from it right away, without further hassle.

Megahertz said:

Format the USB drive partition as Fat32
Make it active.
Extract the iso file files and folders to the USB drive Fat32 partition.

Exactly what I did, but as I said, it either freezes or reboots (and btw, you forgot about files too big to fit on the partition, that have to be converted or split).

However, since I'm doing it on Linux, there must be some differences in the process, resulting in failure. For example, I don't know what's the partition type Windows sets for FAT32 partitions. Is it the same type I set ? (i.e. W95 FAT32 LBA (0x0c)).

NavyLCDR said:

There is no ISO file that you can just copy the ISO file itself to a USB flash drive and boot from, whether it is a hybrid (whatever that is) ISO file or not.

I absolutely agree, and I never said I copy the ISO file to a filesystem on the USB device, that's a rookie mistake. That's why I used the term "burn" with quotes, I was meaning to write the ISO to the raw USB storage device, the same way one restores a disk image. However, that only works if the ISO is hybrid, which MS ISOs aren't. Writing non-hybrid ISOs to a USB raw storage device makes for a non-bootable device. Windows still recognises it, being able to identify storage devices formatted in so-called superfloppy format (one single partition, no partition table, like floppies of the past), but afaik, no BIOS handles this properly, hence it's not bootable.

@NovHak,

I create a Windows 10 bootable USB flash drive in one or two ways. If I have a blank 8 GB or larger flash that can be erased, and I just want to start with the Window 10 installer on it:

1. Download the Media Creation Tool from Microsoft:
https://www.microsoft.com/en-us/soft...load/windows10
Click on Download Tool Now button.
2. Insert the flash drive I am going to use.
3. Run the Media Creation Tool downloaded above.
4. Accept the license agreement, select "Create installation media for another PC", change Language, Edition and architecture if I need to.
5. Select the USB flash drive option, select the removable drive.
6. Let the Media Creation tool create the USB flash drive. It will be MBR with 1 FAT32 partition marked as active and it will boot in legacy BIOS or UEFI computers.

OR if I want to manually create the USB flash drive because maybe it has drivers stored on it I want to keep. I will:

Do steps 1 through 4 above.
5. Select ISO file instead of USB flash drive. I will get an ISO file saved to a location of my choice.
6. If I need to prepare the flash drive I will:

Code:

diskpart
list disk
select disk # <-replace # with the actual number for the flash drive I want to use
clean  <- this will erase the drive selected above make sure it is the flash drive!
convert mbr
create partition primary <- note, the flash drive must be 8 GB or larger up to 32 GB in size (or you have to use /size=)
format fs=fat32 quick <- fat32 partition created this way can only be 32 GB maximum
active
assign
exit
exit

7. Having a prepared flash drive as above, MBR with 1 FAT32 partition marked as active, just like the MCT tool creates, then I mount the ISO file from step 5 above. Windows 8 and Windows 10 will mount the ISO file just by right clicking and selecting mount. Windows 7 and below require a third party program to mount it such as WinCDEmu.
8. When the ISO file is mounted a new drive letter will appear with the files and folders listed from the ISO file. I select all the files and folders on the new drive that appeared - Ctrl + A, then copy them Ctrl +C.
9. Open the USB flash drive in explorer, and paste all the files and folders, Ctrl + V.
10. I now have basically the same flash drive created with the Media Creation Tool. It is MBR with 1 FAT32 partition marked as active, with all the files and folders from the ISO file copied to it. It will boot in both legacy BIOS and UEFI computers.

NOTE: the ISO file created and saved with Microsoft's Media Creation Tool will ALWAYS have a file and folder structure contained in it that will fit on FAT32. You don't need to convert, split or compress anything.

In Linux you can do the same thing, but you have to use GPARTED to create the flash drive and you have to use the DD command to write the contents of the ISO file to the USB flash drive. Unfortunately though the Media Creation Tool will only run under Windows.

You can continue to believe whatever you want to about the ISO files created by the Media Creation Tool, but the above are the real world facts.

I hear you, but as you said, MCT isn't available on Linux !

Concerning dd, you certainly mean cp instead, which is able to recursively copy files, the same way you do with Ctrl+C and Ctrl+V on the Windows file manager (btw Linux has a GUI too, with a recursive copy function through copy-paste). In this context, dd would rather be used to write to the raw device, which doesn't work with MS-provided ISOs.

When I said MCT behaviour isn't reproducible I wasn't meaning it doesn't work. I know it works, it's just that I suspect that installation media created on two different computers with MCT, for the same version of Windows, will have different files. I understand it isn't a concern for everyone, but it can be for some people.

I still have a few options to try, but if things continue to fail, I'm probably going to try MCT on the defective computer running Windows I have handy, or at the very least perform USB formatting with diskpart, so that I can tell what's different between what I did on Linux and what's done on Windows and react accordingly.

There's another possibility though, it's that the Windows machine I'm trying to boot the installer on has a problem that's preventing it to boot it properly !

NovHak said:

When I said MCT behaviour isn't reproducible I wasn't meaning it doesn't work. I know it works, it's just that I suspect that installation media created on two different computers with MCT, for the same version of Windows, will have different files. I understand it isn't a concern for everyone, but it can be for some people.

Not true at all. The same Media Creation Tool will produce exactly the same files regardless of which Windows computer it is run on. The only difference will be that some files will have a different date/time associated with them, which is why the MD5 checksum or SHA hash value will be different.

Did you check that personally, or did Microsoft make an official statement about this ?

There was a thread in the past month where someone had reported problems creating a working Windows 10 iso on an Apple computer. Until now I've not yet seen problem reports for a Linux / Ubuntu installation.

NovHak said:

Did you check that personally, or did Microsoft make an official statement about this ?

Well, ISOs created by the same Media Creation Tool on two different computers and on a Windows virtual machine running under Linux have exactly the same file size, in bytes. So if there are different files in the ISOs they do a darn good job of having them all add up to the same size when the ISO is created.

zbook said:

Until now I've not yet seen problem reports for a Linux / Ubuntu installation.

I'm pretty sure it's a rare situation. But there's also the possibility that I missed something, or there's a problem on the target computer that makes it freeze or reboot when booting off the USB stick.

NavyLCDR said:

Well, ISOs created by the same Media Creation Tool on two different computers and on a Windows virtual machine running under Linux have exactly the same file size, in bytes. So if there are different files in the ISOs they do a darn good job of having them all add up to the same size when the ISO is created.

Yes indeed ! I don't know how that would be achieved on Windows, but on Linux, the following could be done to ensure the two ISOs contents are really identical, assuming $A is the root directory of ISO A and $B the one of ISO B :

Code:

cd $A
find . -type f -exec cmp {} $B/{} \;
cd $B
find . -type f -exec cmp {} $A/{} \;

Not really optimised, but it should work.

cereberus said:

Yeah lots of discussion here but all basically rather off beam.

Right, I've got all information I need to proceed very soon in this thread, and the rest is about addressing some concerns I have that don't really change the problem at hand.

The target laptop is from 2017 and is for the general public so I doubt the latest installer would fail, or at least not just freezing/rebooting like it does. So either I'm doing something wrong, or something is broken in the machine. I will update as I progress.

NovHak said:

Megahertz said:

Megahertz said:
Format the USB drive partition as Fat32
Make it active.
Extract the iso file files and folders to the USB drive Fat32 partition.

Exactly what I did, but as I said, it either freezes or reboots (and btw, you forgot about files too big to fit on the partition, that have to be converted or split).

I didn't forget. We are all supposing that you had downloaded the iso using MCT that has install.esd (smaller than 4G) and will fit on a Fat32 partition. You didn't mentioned if your iso has install,wim (larger than 4G) or install.esd (smaller than 4G).

I suggest you find a Windows computer and run MCT on it to directly create a USB Win 10 installation drive.

Attached is a small batch file to download any version of Win 10 iso.
You can open the batch file and find the link to download the iso without MCT
All_MediaCreationTool.zip
Universal MediaCreationTool wrapper for all MCT Windows 10