Making bootable USB keys
fbsd1 at a1poweruser.com
Fri Sep 4 04:31:18 UTC 2009
Samuel Martín Moro wrote:
> I'm having some troubles, trying to create bootable USB keys.
> I found (freebsd-hackers ML archives) a script, supposed to create the
> bootable image from my iso file.
> But, it still don't boot... (I may do it wrong)
> In details:
> -We distribute a FreeBSD (4.7, 5.4, 6.2 and 7.2) "custom" server.
> -We burn our install CD (and, in a few, our USB sticks) on a Ferdora 9
> -USB sticks must contain a FAT32 partition (we'ld like to provide doc for
> windows users)
> Well, my english isn't so great... so I'll post my code (more
I have same problem with getting a usb stick to boot. After much testing
with different sticks and PC combinations have come to this conclusion.
When usb hardware first can out they were created for usb 1.0 standard
and at that same period PC's where using software drivers for usb
support and the PC's bio's boot selection did not include option to boot
from usb disk. As usb devices became more popular PC manufactures
started adding USB firmware to their motherboards for usb 2.0 standard.
From my research into usb 2.0 it only supports data recording and does
not support booting function. About 2007 usb 2.2 standard came out and
it supports an usb memory stick as bootable. In 2008 some manufactures
of motherboards added usb 2.2 standard to their motherboards and bio's
selection to boot from memory stick.
To be bootable the first file on the the stick has to be the boot image.
Haveing a ms fat partition first on the stick will never work unless
you fill it with an bootable ms/windows or ms/dos system or the same
kind of setup found on the cdrom1 release cd.
Only usb 2.2 memory sticks are bootable on newer PC's that have usb 2.2
firmware on their motherboards and matching Bio's with selection for
booting from usb 2.2 memory sticks. Please note that bio's booting
selection for booting from USB disk is different than booting selection
for booting from usb memory stick. I have posted many posts on this list
about this subject and have not received any posts contrary to the above
The pending 8.0 release has a complete rewrite of the USB code and a new
stick.img is being generated as part of the release install
distribution's. I can dd the 8.0-stick.img file to an 2.0 stick and it
never boots, but do the same thing to a 2.2 stick and it boots on all 3
of my PC manufactured since June 2008.
Final Conclusion: Booting from a USB memory stick successfully is
totally dependent on using new start-of-the-art hardware.
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