So a few days ago I spotted the SDHC discussion thread here, and a couple of days later I found an SD card that fit the dimension: SanDisk Ultra II SD Plus USB. The 1GB version can be picked up for $10 from RadioShack, so I think I should give it a try.

First I trimmed down the card so it can fit in the RS-MMC slot. It took me 20min, and it wasn't very bad as soon as I figured out the internal structure. I taped the USB portion and some contact points exposed, stuck the card in my 770, rebooted the machine (the booting procedure somehow skips the MMC cover check). The card was recognized and I can format and put swap on it. Great!

Then, I started to cut the USB portion. I was very conservative and tried my best to cut as far from the SD portion of the circuit as possible. But when I almost finished cutting, a thought suddenly poped in: what if the USB portion of the circuit somehow is also involved in accessing the card? Well, it is already passed the point of no turning back...

Finally, after carefully cleared up the damaged part of the board, I tried the card again with finger crossed. But, there was no luck, the card is dead.... >_< ... I also tried with an external SD card reader, the activity LED blinks regularly (so maybe the card isn't completely killed), but the card wasn't recognized...

Anyway, for $10, I got a keychain SD card holder... better than nothing

So, the lesson for other DIYers: don't repeat what I did... :P

They still sell the 1 GB RS-MMC cards at Newegg.com

$8.59 with $5.99 shipping

Yeah I already have a 1GB RS-MMC. I am just trying to check out if it is possible to easily convert SanDisk Ultra II SD Plus USB to fit in N770 - if that was possible, I can get a 4 or 8GB version and DIM (Do It Myself)...

Check out this, I have one and it is great. As long as when you reflash you don't start to freak when it does not work right away, since you need the SDHC kernel to see the card.

Wow, 8GB for 770, nice work. But $75 is a bit expensive. I only paid $110 for my 770.