El Capitan’s Boot Camp has USB drive-less Windows setup, but not all Macs are supported

OS X El Capitan Boot Camp Assistant app icon full size

Boot Camp, the Mac’s built-in software for dual-booting between OS X and Windows has been given some love in the new El Capitan software update and now features a slicker Windows setup that no longer requires a USB thumb drive, as discovered by Twocanoes.

Previously, Boot Camp required that the Windows installer be provided in the form of a USB drive or CD/DVD installation media. Now you can just point to an .ISO file, which significantly shortens the entire procedure for those who have purchased Windows as a digital download.

The first thing you’ll notice when you open Boot Camp Assistant on a new Mac that supports Windows 8 or later is the all-new Boot Camp interface.

OS X El Capitan Boot Camp Assistant Mac screenshot 001

As you can see for yourself, you no longer need to insert a USB Flash Drive as Boot Camp Assistant can at last copy the Windows installer directly from an ISO disk image.

This drastically shortens the Windows setup process as you literally just select the ISO file and how much space you want from Boot Camp, and then you click Install.

“After Boot Camp Assistant completes, OS X restarts to the Windows installer, and you follow the normal Windows installation,” reads the article.

New firmware magic

This is possible due to the new EFI firmware software on El Capitan.

Boot Camp Assistant basically creates an additional FAT32-formatted partition called “OSXRESERVED,” in addition to a Boot Camp partition. The OSXRESERVED partition has all the installer files, the Boot Camp drivers for Windows and the EFI firmware files for booting.

OS X El Capitan Boot Camp Assistant Mac screenshot 002

After the Windows setup process completes, the OSXRESERVED partition is removed during the next boot into OS X.

Is my Mac supported

Turns out this slicker way of installing Windows requires Mac hardware which supports the new firmware that makes this possible, including these models:

  • Mac Pro
  • MacBook Air 13‑inch
  • MacBook Air 11‑inch
  • MacBook Pro 13‑inch
  • MacBook Pro 15‑inch

The following Mac models still require a USB flash drive to install Windows in El Capitan:

  • iMac 21.5-inch
  • iMac 27-inch
  • MacBook Pro 13‑inch
  • MacBook 12-inch with USB-C

Apple also appears to have changed how Boot Camp is affected by El Capitan’s new System Integrity Protection (SIP). Also known as “rootless,” SIP prevents malware from modifying system files even if you’re logged in to your Mac with system administrator (“root”) privileges.

Source: Twocanoes via The Loop