This may upset some people but I wanted to do it for the sake of doing it. What I present for you is a method of running Firefox From your USB drive/device and have the security to know it was the Official Mozilla build that you are using. This can be performed from DOS, a shortcut, a program launcher, etc. And right about now you're waiting for the ultimate weapon so here it is.
Firefox -profile "[Profile path]" -turbo
Now [Profile path] can be anything, relative, absolute, as long as you don't end it with a trailing back slash.
"E:\Firefoxdata\Profile\"Fails with a program crash.
To make it even better you don't need to invoke
-CreateProfileto generate a profile, you just need to provide a specified directory. And Firefox will make one for you. Sweet eh? And yes, I included
-turbonot for good measure, but because it makes Firefox load that much faster. Much faster than just UPX'ing it. I'll be making a similar post concerning Thunderbird.
I used the information supplied here to help make this post.