https://www.reddit.com/r/GameAndWatchMods/ Look down the sidebar on the right for the list of Macronix chips. The 16MB are the easiest in terms of the software, because it doesn't require any changes. They're also the easiest in terms of soldering because they have legs like the chip that's being replaced. The 64MB needs patches to the software before you flash it, but that's available now for the current software, and will be figured out by the clever people for any other software that's coming. The 64MB chip also doesn't have legs, so is apparently noticeably harder to solder, but not impossibly so. I haven't done any of the soldering yet so I can't speak personally of the difficulty. (I haven't seen any discussion of the 32MB chip, software patching would be the same as for 64MB, I don't know if the chip has legs).