Originally Posted by perbh
Your insight and knowledge about boot problems are impressive - infact, I would recommend _anyone_ with the slightest hint of boot-problems to read your postings here - the moderators should make it sticky!
I pride myself to be able to solve most boot-problems, and like you, I prefer legacy grub and chainloading (always having at least 2-3 distro's on each disk) *chuckles*
But also I have run into problems - like using slackware on a big (like 32 gigs) usb-stick and hoping to boot it on any computer ... the problem being that uuid's are not known until the kernel (or initrd) is loaded. When you boot from a usb-stick and use bios to select it - initially it is 0x80, but then, as things load, it will end up as sdb, sdc etc - dpeneding on the number of hard-disks in your system *sigh* - it certainly is hard to get it right. What I did in my particular case was to assume only one harddisk in the host and when it failed to boot - to pay attention to where it ended up - then reboot and edit the grub 'kernel'-entry *lol* - it works ...
USB sticks is an interesting subject for another thread. I've run into the problems you describe as well as a few others. Windows, for example, refuses to see more than a single partition on a removable drive. Add to that the complication that some BIOS software does not consider a USB drive a boot device unless it sees multiple partitions. There are the older computers that don't support USB disk booting at all; Some that only support USB CD booting; And some that have horribly slow USB emulation, making a CD actually faster than USB sticks. I'm still learning about making USB boot media. Here are a few links that you may find useful.
Explanation of U3 vs other flash drives
Tools to make custom U3 CD images
USB CD Rom Emulator