Nice. My own 2,1 does boot with the new memory but there's definitely a power fault somewhere since the battery doesn't charge, and hooked up to the power, it might turn on for a few seconds while the charging light is amber but shuts off again when it's green. Or I could (should) just replace it with another 2,1 board...
How hard was it to swap them?
Just ordered it so we will see! I will report back here once done.
Good luck! It's not impossible to put a 5,2 A1181 motherboard in a black A1181 case -- the only thing to watch out for is that the screw bosses on the bottom case won't fully match the screw positions on the motherboard (regardless of what A1181 variant you're putting the motherboard into), making fitting the heatsink problematic. One person used a copper shim to ensure proper contact between the heatsink and the CPU, but I find that kind of solution somewhat worrying (especially since they mentioned that in their case only one screw was able to fasten the heatsink to the motherboard).
IIRC, the legendary dosdude1 did this when he did his "World's Fastest A1181" CPU transplant mod, and solved the above problem by taking a Dremel to the plastic standoffs on the bottom case holding the metal screw bosses, cutting them from the bottom case, and simply supergluing them into the correct positions for the 5,2 motherboard's heatsink. I suspect that's what you'll have to do here.
Oh, and since you took out the SuperDrive, you'd might as well put in its place an optical drive bay caddy for a second hard drive or SSD (it's easy and affordable since the 5,2 used SATA for the optical drive, and SATA-SATA optical drive bay caddies are cheap and relatively easy to find). I've said before that this is one of my favorite upgrades for the 5,2.
Also: I had no idea the 5,2 could support 8 GB RAM. I've always seen 6 GB mentioned as the maximum, but after looking into it, I've just read posts from folks on the Apple Support Forums saying that they've gotten 2 x 4 GB DDR2-667 SO-DIMMs working. Wow. I hope you were able to get 2 x 4 GB DDR2-800 SO-DIMMs for a good price! (I always complain about how expensive they are on here...)
Very good to know - I actually forgot to even order a heatsink for it as the board comes without it, so I just grabbed one for another $11 - still not a bad upgrade for $22!
I'll see what I come up with on fitting the board. Fingers crossed. If I pull it off I may even do the A1260 multitouch trackpad mod someone else did - if I can find a black sticker to cover the silver pad.
I was actually looking at the optical drive bay caddy before I planned to upgrade the board, so you're right, now that it's going to have SATA there I might as well! Now the question is...do I throw in the original HDD or spend even more money on this little guy and get another SSD? I'm sure I could find one cheap enough.
As far as the RAM goes, I already had it here, not being used so thankfully I did not have to pay current prices for it lol.