OK, first of all...

I have NONE of the backup files that were created on the first flash.

Before someone says "there's no excuse for that"... There sure is. This was originally flashed for a friend. We traded boxes much later. (Exploits/Drive Preferences) For some reason, he had deleted the backup files.

The drive, and the Xtreme4.x both WORK. I just want to upgrade the firmware.

This guide is awesome http://forums.xbox-scene.com/index.php?showtopic=573381#

However i'm having difficulty solidly interpreting:

Is it saying I can just dump my 4.x extreme as the orig.bin, and use the key from THAT?

Yes go to How to recover your X360 drive key, you will be able to dump the firmware currently on the Drive.

then using FW toolbox on that file you will be able to get your key and continue with How To Update To Xtreme 5.3: Tutorial, Xtreme Boot maker / Via card method

good luck

-soso

Thank you

this is the post that i havfe been looking for ty