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I'm using the Ultimate Boot CD, and I've added a bunch of customized .iso's to it. I can boot into those .iso files fine, but most of them are mini-versions of Linux that are designed to run off of a CD. When they try to boot, they try to run off the CD (which obviously isn't there since they're on a USB drive) and then either freeze, or don't work in some other way.
Is there any way to edit the .iso files to tell them they're booting off of a USB drive? I'm assuming there'd be something somewhere in the boot configuration files to do this. Where would that be? I would think it'd be different for different ones, but are there some places that are standard for live CDs? What would I have to change?
EDIT: Just to make exactly what I'm asking clear...I know there's stuff all over the place on how to boot a .iso from USB. That's not the problem, I can already do that. What I'm wondering is how to make the OS stored in the .iso realize that it's booting from USB and not CD?
There is no difference. The problem you are describing really can't be caused by booting from a Flash drive instead of a CD drive. (Both are/can be USB.) You have a faulty disk image. – CarlF – 2011-09-06T19:39:36.880
I think the problem is that the .iso's use syslinux (or isolinux) to boot, and I think those systems are designed to boot off of a CD. I think there are ways to edit them to boot off of USB, however I'm not exactly sure how to do that. So I'm thinking there are two ways to go about it...either edit each individual .iso file and configure isolinux to boot from USB (I'm not sure how to do that) OR somehow make the flash drive seen as a CD-ROM drive by the BIOS (I'm not sure how to do that either ;) lol – Mako – 2011-09-06T20:14:15.360
Really, that isn't the problem. Either you have corrupted disk images, or you used Unetbootin wrong. They work great for the enormous majority of people. It's also possible that your flash drive is defective or your computer doesn't boot properly from USB due to BIOS problems. – CarlF – 2011-09-06T20:32:10.667
The USB boots fine. I'm using syslinux from the UBCD to then boot into (just for example) AOSS (which also uses syslinux). So I'm going from one boot menu, into another menu, into the OS. The problem is after the OS tries to boot, it fails. I noticed that in "isolinux.cfg" inside the .iso it had "boot=cdrom" so I changed it to "boot=usb". (Found that on a forum somewhere.) But it still didn't work correctly. – Mako – 2011-09-06T20:42:40.960
Again, it works fine for every other Unetbootin user. Try a different bootable distro, e.g. Knoppix, Ubuntu. – CarlF – 2011-09-06T20:52:39.617
Well it's clearly hit or miss with which .iso files will work...ideally the USB flash drive would emulate a CD...then when Linux mounts something at /dev/sr0 or /dev/cdrom it would be talking about the USB drive. – Mako – 2011-09-06T22:20:04.157