Originally Posted by locoroco
I need to boot the ultimate boot cd
from an usb stick. Do I just copy the iso image to the usb key?
How do I make the usb stick bootable?
We get asked this all the time
. Maybe we should make it part of the FAQ.
- There's no magic "make bootable CD into bootable USB drive" program. They're too different to be directly compatible with each other.
- Sometimes you'll find special tools like the program which makes Win7 ISO's into bootable flash drives, but that only works for specific versions of specific programs; it needs to be able to understand them, and reconfigure them for the different boot device. This is because:
- A USB flash drive isn't a CDROM, period, no ifs, ands, or buts. You can't fool the BIOS into believing it is. It will believe it's a hard drive.
- This means dumping an ISO image onto a USB drive won't work. The BIOS won't know what to do with it.
- You need different bootloaders to boot from a USB drive rather than a CDROM drive anyway.
- You could install your own bootloader, and build a custom initrd containing minimal software allowing it to mount an ISO image off of the USB drive, and chroot into that. But the ISO file probably expects to be run off of a CDROM, and will complain mightily about not being able to find its contents -- unless the distro has special arrangements to allow you to tell it where to find itself. So it depends on the distro.
A USB drive is a hard drive as far as the system's concerned. Booting from it generally means either installing on it like it's a hard drive, or using some special arrangement a particular distro might have for booting from USB disk.
None of this is necessary for what you want however which, last I checked, was running memtest86. You can boot a kernel
with kexec. Just find the memtest86 kernel inside those ISO's and kexec into it.