Bootable USB Keys

Filed under Hardware, Utilities

Maybe I’m jumping on the band wagon a bit late with this one, but it’s pretty slick if your machine’s BIOS will support it.

It IS actually possible to write a boot sector and boot files to those little 256mb+ USB keys that you can get in the gumball machine down at just about any local soda fountain or 10 cent store these days.

Why would you want to?

  • They boot a LOT faster than CD or DVD
  • They’re rewritable without any special considerations.
  • You don’t have to have special burner software to update them (other than what’s required to lay down a boot sector).
  • You don’t have to suck up an EIDE channel just to be able to hook up a CD to boot to.

It was that last part that hooked me. I’m in the process of upgrading a TIVO to 320GB and my shiny new iron only has 1 EIDE port (and 2 channels). One to the old TIVO drive, one with the new drive and, bang, nothing to boot to (You don’t want to boot to Windows with your TIVO drive attached, Windows like to stamp any drives that it can see, which can screw your TIVO drive all to hell).

With a bootable USB key with MFSTools on it, I can boot to the USB, and still have both the HD’s connected to copy and back up between them.

I know, I know. Grab an old machine with 2 IDE ports and my problem was solved. Well, the only old machine I have left is way, way old, and it’s bios doesn’t even recognize the 320gb drive I’m using to upgrade. The other, not so old machine, is just waiting to be hauled to the hazardous waste site, cause it won’t even give up a POST BEEP.

To get DOS or windows on the disk, you’ll need to format the USB Key with a boot sector. The easiest way I found to do that is this HP utility. It should let you format the drive and copy the boot sector over from a boot floppy. Once that’s done, you should be able to grab a copy of BARTPE and build up a fully USB KEY bootable copy of Windows XP, assuming you have a bootable CD of Windows XP. Well, it ain’t a “full” Windows XP but it’ll get you loaded and able to grab info of an otherwise unbootable drive.

To get Linux working, you gotta go deep. You’ll have to use SYSLINUX, and/or ISOLINUX to overwrite the DOS boot sector with a LINUX boot sector.

To get MFSTools working on the resultant LINUX USB key, you’ll need to get the ISO first. Mount it using something that’ll mount ISO images, like Elaborate Byte’s free and excellent Virtual Clone Drive. Then copy the whole thing down to the USB key. This won’t copy the boot sector, though. That’s what SYSLINUX was for.

Still won’t quite work though. You have to copy the contents of the ISOLINUX folder down to the root of the USB key. Then Rename ISOLINUX.CFG to SYSLINUX.CFG. That’ll allow the ISOLINUX image to boot to a ram drive like it does normally when booted from CD (at least, that’s the way I understand it, knowing what I know about Linux at this point).

If all that’s done right, and assuming that your machine supports booting from USB, and assuming you’ve configured the BIOS to allow it, reboot and feel the joy.

If it doesn’t work, take two aspirin, reboot and… be thankful Windows doesn’t require this sort of nonsense….???? Ok. I jest.

BartPE is a very interesting possibility because it’s relatively easy to build and you can add your own Windows tools to the mix (up to the size of your USB key anyway). Could come in very handy for recovery and forensics work. And USB Keys are more scratch resistant than CD’s. Plus, some have that nifty, switchblade action with the USB plug.

image or image

Oh, and one final tidbit for any security oriented people, check this out and see if you get any sleep that night.

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