Unfortunately, I'm not well-versed in that sort of cheat hacking. My area of expertise is the various types of known/unknown value searches, as well as memory poking.
How would I go about, say, hacking a code to disable the death routine when one falls into a pit in Super Mario Bros. 3 (being played via my PSP-based emulator, NesterJ v1.13)?
I'd need to re-code that particular part of the game which deals with the death routine, to make Mario reappear at the top of the screen if he falls into a pit, or, somehow enable the "invisible trampoline" effect if he happens to do so (bounce on the "bottom" of the hole). I've never tried to do something of this nature (at least not in an NES game), due to the fact that I can usually achieve what I set out to do with the types of searches/pokes I mentioned in the first sentence of this post.