ok, fun times. 0020 error.
current system is sammy ms25 that was a replacement for a release day 360 that was scratching my games. It's got latest firmware on it. got 3 flashing red lights with no advanced warning whatsoever. Loaded a backup like 20 minutes earlier and worked awesome. Decided to throw something else in and was greeted with the 3 flashing lights of doom. Code was 0020.
Tried this trick with a pink eraser and a product known as glue dots. kinda like double sided tape somewhat. I was honestly not too hopeful it would work so I didn't really go to great lengths to make sure the eraser pads were 4mm. Probably closer to 5 or so. Upon piecing together the motherboard, I hooked up the cables before screwing the top on and let her rip. I got one more 3rlod, turned off, restarted, then BAM!, it works perfect. Loaded up GOW and let it run in-game for about 20 minutes. All seemed well.
Put all the screws in, pieced the box all together again, hooked it up. Then wouldn't you know it? I got 2 flashing lights now. 0011 I think was the code. Overheating. So I broke it open, made sure it worked with the screws out again, which it did, then put the screws back in but very loosely. It did take some trouble shooting but I found the little black screws needed to be tight(er) than the silver ones. If the black ones were lose, for some reason I would get the 3rlod again for some reason. Who knows.
I hope this helps someone. Pretty stoked I don't have a 400$ brick... for now (knocks on wood)
oh, and I'm planning on leaving GOW run overnight while I sleep. Hopefully this will tell me if this fix will last a while.