Boot OS X Lion From USB Flash Drive [Guide]

Mac OS X Lion has been released yesterday, But only on Mac App Store and Apple announced that there won't be any physical DVD Copies from Lion, However a $69 USB flash drives of lion will be available in August. Here is how to get one before August.

First of all you will need to Access to the Mac App Store and a working Apple ID so you can purchase and download Lion. Also an empty  flash drive with at least 4GB of memory, 8GB would be better.

Here's what we will do:

Step 1: Download OS X Lion from the Mac App Store.

Step 2: Once downloaded, go to the Applications folder and find the copy of Lion you just downloaded.

Step 3: Right click on the downloaded file and select “Show Package Contents”.

Step 4: Go to “Contents” and jump inside the “SharedSupport” folder and you’ll find a file titled “InstallESD.dmg”. Copy this over to the desktop.

Step 5: Plug in a USB flash drive to your Mac having at least 4GB memory. We highly suggest going ahead with an 8GB one just to be on the safe side.

Step 6: Now open up “Disk Utility” and drag InstallESD.dmg from the desktop to the left-hand sidebar. Select the attached USB from left side and click on “Partition” tab.

Step 7: Select “1 Partition” from the Volume Scheme dropdown menu. Choose “Mac OS Extended (Journaled)” from the left.

Step 8: Now click on “Option” at the bottom. Select “GUID Partition Table” and press OK. Now click on Apply at the bottom right to start formatting.. (NOTE: This is will erase all data on your USB flash drive)

Step 9: Once the drive has been formatted, click on “Restore” (it’s right next to where you clicked on “Partition in Step 5).

Step 10: Choose USB drive you plugged-in in Step 5 as “Destination” with the InstallESD.dmg file as “Source”.

Step 11: Click Restore and type in your password. This will create the intended Lion bootable USB flash drive

Step 12: Reboot your Mac with the USB drive plugged in. Hold the “Option” key on your keyboard when you hear the iconic OS X startup chime. You can now boot into your Flash drive from there.

Step 13: Follow the on-screen instructions to install OS X Lion.

You may then follow Steps 12 and 13 to install Lion on all your Macs.