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I'm sure this sounds like a question that's been answered a million times, but I can't find anything related to what I need.

What I have is a USB drive that, as far as I can tell, has been formatted correctly, with three partitions, one being bootable with a windows installer. I've checked the MBR and that parition is set to bootable and active, but the bios just doesn't seem to want to pick it up. I have everything in the BIOS set up correctly (I've done this a million times before) but it doesn't want to detect the bootable drive.

Is there a simple bootloader that can be burnt to a CD or a thumbdrive that loads, detects all paritions (such as hard drives or, in this case, USB partitions) and manually forces a boot from that partition?

Nothing I seem to google helps. Thanks!

EDIT: I downloaded a super-grub CD iso and burnt/booted into it. It will detect my little 1 gb thumb drive but not the external harddrive. However, I can plug the hard drive into my laptop and everything will work just fine. I'm beginning to think this is a BIOS error or something.

Any thoughts?

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What exactly happens when you try too boot from that device? Is USB boot enabled in BIOS? Checked the pen drive on some other system? Edit boot sequence from BIOS and remove everything except USB device from there. – tumchaaditya May 25 '12 at 9:09
I've done all of that. The BIOS is just lacking any sort of intelligence; the other PC shows up just fine. It seems to only like true, single partition thumb drives and the built in hard drive; and, of course, CDs. – Qix May 25 '12 at 9:14
what exactly do you have on the thumb drive? how many primary partitions on thumb drive? – tumchaaditya May 25 '12 at 10:09
Sound insane but it will be worth to delete all partition on USB drive and create only one and then try to make it bootable. – avirk May 25 '12 at 11:26
@tumchaaditya - Three partitions; one has an ubuntu installation, the second has a windows installation, and the third is just file storage and backup. – Qix May 25 '12 at 23:40
up vote 1 down vote accepted

Almost all Linux distros have a bootloader as part of their LiveCD/Installer. You could boot off that, and when presented with the boot menu add an entry to boot off your USB.

However, if you can successfully boot off other USB devices I'd hazard a guess that this wouldn't help you as it's not selecting the boot device that's the issue (your computer would already be doing this), but instead that the USB device isn't set up correctly. Flagging a partition as "bootable" is only a small step in successfully booting.

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