Tuesday 21 September 2010

Create A Bootable USB Flash Drive Larger Than 4 GB

With the advent of larger and larger OS installs that come on dual layer DVDs (8 GB+), we need to revise our previous post methodology for these new OS files on a bootable USB flash drive.

The methodology we have been using for USB flash drives with large OS install files has been the following (Assume [Enter] after each command line):

  1. Start –> Diskpart (type in search)
  2. Right click on Diskpart and Run As Administrator
  3. Click Continue if prompted by UAC.
  4. List Disk
  5. Select Disk 3 (use whatever number in place of “3”)
  6. Clean
  7. Create Partition Primary
  8. Select Partition 1
  9. Format FS=NTFS Quick
    • Make sure to have the Quick switch or it will take _a long_ time!
  10. Active
  11. Assign
  12. Exit

Now, we can run the above commands using their abbreviations:

  1. Lis Dis
  2. Sel Dis 3
  3. Clean
  4. Cre Par Pri
  5. Sel Par 1
  6. Format FS=NTFS Quick
  7. Act
  8. Ass
  9. Exit

The following is a screenshot of the above command set being used to format an 8 GB OCZ Rally2 Turbo USB flash drive:


Once done we can copy the OS files off of its ISO using Virtual-Clone Drive (SlySoft Site) to mount that ISO with a drive letter in Windows.

This method requires Windows Vista, Windows 7, or server OS with the same code base or newer.

Note that there is no requirement to edit the Boot Configuration Database at all (BCD). We have been using this method for a while now to install beta OSs in our lab here without an issue.

We sometimes drop a Drivers folder on the USB flash drive too. As a just-in-case we add the Everyone NFTS group and give it FULL permissions to the USB flash drive after running the above steps.

Philip Elder
Microsoft Small Business Specialists
Co-Author: SBS 2008 Blueprint Book

*Our original iMac was stolen (previous blog post). We now have a new MacBook Pro courtesy of Vlad Mazek, owner of OWN.

Windows Live Writer


Seanpt said...

Call me crazy but I don't use the abbrs in diskpart since I'm dealing with disks and partitions and issuing commands like clean.

It doesn't take me any extra time to type the full words so I'll just stick with that as a way of making sure I'm not about to select disk 1 and clean it!

(When one of the early guides for this method came out it showed the example of selecting disk 2 and cleaning it and quite a few people lost a lot of data from blindly following the guide.)

Philip Elder Cluster MVP said...


No worries. You do have a point as far as running through the commands and that is that I assumed that folks would choose the _flash_ drive to work with!

The flash drive will be 4 GB, 8 GB, 16 GB or thereabouts in size! Selecting an 80 GB or 300 GB partition from the list would definitely fall outside the scope of these instructions.

The abbreviations come as a result of running the process so many times. We have around 14-16 flash drives used for OS installs at any given time.

Sometimes they need to be formatted prior to dropping an OS on them.