When I said "It's pretty hard to mess up a RAM upgrade to the point your Xbox isn't functional" I meant, to the point where you can not recover your mobo. But then again, I agree with A@ron.
Uhhh, why do you say that?
I will admit, the very first one I tried yesterday didn't go as well as I hoped. Actually, all of it did but one piece of memory. I managed to get excited towards the end (being the first RAM upgrade) and soldered it SLIGHTLY off center (which makes a HUGE amount of difference). I could tell, at the end, I had some bridging going on just because of that, so I removed it all ouf of disgust and anger.
So I took a nice, lonh 4 hour break from soldering and gave it another shot on a different motherboard... this time with much more patience and attention to minute detail. By doing that, it went much more smotthly than the first attempt. It booted on first try.