- Rufus create bootable usb image windows 10#
- Rufus create bootable usb image code#
- Rufus create bootable usb image iso#
- Rufus create bootable usb image windows 7#
- Rufus create bootable usb image windows#
You can also create disks that can boot from both BIOS and UEFI, which is how most ISO are setup too.Įdited by Chiragroop, 22 October 2019 - 10:22 AM.ĭd is a handy tool as part of hiding files in plain sight (Steganography). It does not work on 4K Advanced Format hard drives. The reason is that Windows' VBR for FAT32 only works on disks with block size of 512 bytes (which is all USBs and older 512 and 512e hard drives).
Rufus create bootable usb image windows#
I wanted to edit my original post to include the above, but I could no longer edit it so I did it as its own post.Įdit: FAT32 is not as reliable for BIOS booting Windows from internal hard drive as compared to NTFS. In GPT, it creates a special partition called BIOS Boot (in Gparted) of 1 MiB for Stage 2, since there is no empty space to stash stage 2 like there is in MBR. The interesting thing is that Grub can boot in BIOS mode on a GPT disk as well. This finally can load the 3rd stage or 4th stage. This leaves around 31 KiB of space, which is used for Stage 2 (and modern OS typically leave spaces of 1 MiB so it still works out today as well). Generally, due to the whole CHS legacy system, the first partition in MBR starts on the 64th sector. Stage 1 can be stored in MBR or VBR/PBR of a partition. GRUB in BIOS has multiple modes and works in stages. This means that your disk should be bootable if you copy all the files in the ISO to it in BIOS mode by just marking the disk as activeįor Linux, I will only go over GRUB. If you are wondering how this works, this is because every disk that you format has an MBR that is OS-independent (in that, all it does is look for the partition that is marked active and load it's VBR/PBR (different terminology but means the same thing)), and every FAT32 and NTFS disk that you format in Windows has a VBR that looks for bootmgr at the root of the disk and loads it. Both worked in Virtualbox with EFI mode off.
Rufus create bootable usb image windows 7#
Then, I copied all the files in the ISO in there for Windows 7 SP1 and Wind(separately). Rather than formatting as NTFS, I formatted the disk as FAT32 with the MBR partition scheme. I ran another test where I created a disk image of the size 5 GB for BIOS booting.
So, I split the wim file by following the instructions here: Įdited by Chiragroop, 21 October 2019 - 12:43 AM.
Rufus create bootable usb image windows 10#
TLDR: You can copy the files into a FAT32 partition for UEFI boot (works for Linux and Windows ISO), and if you want to boot Windows in BIOS mode, you format the USB as MBR, create an NTFS partition, copy all the files in ISO in it and mark it as active.Įdit: I have also used this method on Ubuntu ISO and Windows 10 (though Windows 10 was a little tricky because on some ISO files, the install.wim is larger than 4GB and FAT32 has a limit on the maximum size of a single file as 4GB.
Rufus create bootable usb image code#
Then, when the NTFS partition code loads, it looks for a file called BOOTMGR on the root of the partition and loads that, starting the boot process. You also must mark the partition as active. For this to work for Windows ISO, you have to format the disk as MBR and the partition as NTFS (this is important for BIOS booting only, as UEFI booting can work in FAT32 partition just fine). The way BIOS boot works is it loads the MBR, which loads the code on the active partition. In fact, if you take a look at the ISO, you will notice a folder called EFI on root and if you look inside, you will find /EFI/Boot/Boot圆4.efi in it.įor BIOS booting, I will only talk about Windows and normal USB booting (as Grub and El Torito boot are far more complicated and DVDs/CDs are rarely used for booting installation media anyways). From there, it looks for a file /EFI/Boot/Boot.efi So, for x86-64 computers (basically all computers that are 64-bit), it is boot圆4.efi. The way it works is that there must be a filesystem that UEFI understands (with FAT32 usually used since UEFI standards specify that FAT file system must be supported at the very minimum). That said, there are some firmware that do things like switch to CSM (Legacy Boot) if they see the MBR partitions so they do not adhere to the spec and GPT may be more reliable). As far as UEFI is concerned, it can boot from MBR or GPT partitions (It is only Windows which mandates that UEFI booting requires GPT partition. I will go with the newer UEFI booting first, since it is far simpler.
The way it works is actually interesting, but it diverges depending on what type of computer you have: the older BIOS-MBR booting or the newer UEFI booting.