Preparing the flash drive
It’s pretty easy to build single-boot flash drives – even for Windows 7 or 8. They can serve as installers or as live devices that can run an OS or repair utility without being installed to a hard drive or SSD. Drive formatting varies somewhat depending on whether it will be booted in legacy (BIOS) or UEFI mode or if it’s going to be a Windows flash drive. I’ve found it’s almost always necessary to prep the flash drive, even if already seems to be formatted appropriately. These things often come from the manufacturer with a strange formatting scheme.
I’ll give a generic example of drive prep using Windows 7 DISKPART. This can also be done from Linux using any of several tools. Run DISKPART from a command prompt. This is an example and will look different on other machines. The red (notes) aren’t part of the command line conversation and try to flag the different requirements for the two boot schemes – and offer a warning. Please see below for details.
C:\Windows\system32>diskpart Microsoft DiskPart version 6.1.7601 Copyright (C) 1999-2008 Microsoft Corporation. On computer: Z77 DISKPART> list disk Disk ### Status Size Free Dyn Gpt -------- ------------- ------- ------- --- --- Disk 0 Online 238 GB 0 B Disk 1 Online 465 GB 1024 KB Disk 2 Online 1863 GB 0 B Disk 3 Online 29 GB 0 B DISKPART> select disk 3 (note 1) Disk 3 is now the selected disk. DISKPART> clean DiskPart succeeded in cleaning the disk. DISKPART> create partition primary DiskPart succeeded in creating the specified partition. DISKPART> select partition 1 Partition 1 is now the selected partition. DISKPART> format quick fs=fat32 (note 2) 100 percent completed DiskPart successfully formatted the volume. DISKPART> active (note 3) DiskPart marked the current partition as active. DISKPART> assign DiskPart successfully assigned the drive letter or mount point. DISKPART> exit
Notes: 1) Be absolutely certain you select the flash drive. Otherwise you’ll b0rk one of your system drives. 2) Use fs=ntfs when preparing a Windows 7 legacy boot installer. Use fs=fat32 for Windows or Linux UEFI and Linux legacy booting. 3) The active command isn’t needed for UEFI boot (it won’t hurt anything, although it may confuse a UEFI+legacy BIOS into booting in legacy mode) but is necessary for legacy booting.