Good effort on the step by step instructions.
I followed the instructions a few times, but I could not get it to work. I'm using Ubuntu on a Dell laptop. I did manage to get the presistent usb install to work with a few changes.
When using fdisk, I found Ubuntu can mix up /dev/sdb1 with either /media/disk-1 or /media/disk-2 when the usb drive is mounted. This can lead you down the wrong road quickly.
To fix this, I made first partition with fdisk and wrote it. Unmount and remount the usb drive. Ubuntu will call this /media/disk-1. Then make the 2nd partition and write that. Ubuntu will call this /media/disk-2.
Now, /dev/sdb1 is equal to Ubuntu's /media/disk-1 and /dev/sdb2 is equal to Ubuntu's /media/disk-2. This makes it less confusing.
When following your instructions, I changed
"cp -r boot /media/disk" to "cp -r boot /media/disk-1
"cp -r BT3 /media/disk" to cp -r BT3 /media/disk-1
In /dev/sdb2 (/media/disk-2 in Ubuntu), you need to make a folder named "changes", if I didn't have this folder, the USB stick did not boot properly.
If you have a Dell laptop, add "acpi=off" to syslinux.cfg or type it in manually on boot.
I could not get it to boot if I didn't have this added with the USB install or live CD.
Those were the only issues I had with the instructions.
I still have 2 problems. About 1/2 way through the USB boot process, I get a black screen for about 1 minute, then everything starts up fine. I don't know if this is normal or not.
The other problem is that I never get a clean shut down. I get a fatal error and I have to manually turn off my laptop. I Googled this problem, did not find any good fixes so far...