Boot from USB drive without bios support

Post your suggestions here if there are new features or applications that you would like added to the Ultimate Boot CD.

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Boot from USB drive without bios support

#1 Post by bitbanger » Fri Jun 01, 2007 8:49 pm

I am still trying to understand all the wonderful support UBCD provides. Very impressive!

I would like to see an option to boot from a usb device when this support is NOT available from the bios. This is often the case when using an older machine. Or even a new machine where the system designers were not paying attention to the real world.

As cheap as USB-HDD are it make a lot of sense to install linux to an external drive leaving your installed Windows system alone. Dual boot systems can frighten some people away.

I include the following link
from someone who claims success with a particular methodology. I do not have the expertise to duplicate the effort.


Victor Chew
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#2 Post by Victor Chew » Sat Jun 02, 2007 5:34 pm

Someone correct me if I am wrong.

From my limited technical understanding, I don't think there is a generic approach to this problem.

The best one can do is to go for an OS-specific solution eg. certain Linux distros have their own boot floppies/CDs for booting a USB device on non-supporting hardware.

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#3 Post by Constance » Sun Jun 03, 2007 9:44 am

This idead reminds me of programs to overcome the old 1024 cylinders BIOS limitation, that could be installed in HDDs' MBR ... so I suppose it could be done somehow, yet I don't know one.
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Comparison of a sort

#4 Post by bitbanger » Sun Jun 03, 2007 4:35 pm

I remember when CD hardware was the archetypical nasty device. The drivers were a headache to install and the result was quite unreliable. Now CDs are so well behaved that you can boot from them. In fact, they are now the most common boot media for installations.

If I am understanding the situation correctly bios boot code is not that large. I recently got a bios update for one of my computers and the bios update and install code is only 234K bytes. If USB boot is possible in such a small program why cannot the same code be provided from some other source? Code is code, right? There is certainly lots of room left on the CD with the current UBCD.

No bios that I am aware of will boot from the second hard drive but UBCD will do this. So the limitations of the bios are not critical to a feature. UBCD is booted from and then, using the appropriate magic, the boot process passes onto the second hard drive. Do the same for a USB device.

It should not matter if the UBCD boot from USB option is Linux or Windows, the eventual target takes over and the boot code is paved over.