Between regions there is no foolproof way/simple way (between devices can be done). You are going to have to remake the code but as you already have a code it might make sense to look at that- sparing a crash course in computing theory in favour of a few sentences type thing
The gameboy has banks of ram that store data (like how much ore you have) which then gets shifted back and forth between the save memory.
When you compile a program made using a high level language (as this probably would have been) with differences it can radically change where data ends up in ram (one of the main point of high level languages like C is to avoid you having to take care of the ram).
Cheats on these devices however are simple things (modern ones can be slightly better but do not count on it) that contain a memory location, a type of operation (hold, inject, add, subtract etc) and a payload if necessary (some operations do not require it).
The change in memory location (say for a different region, version and the like) will mess up the cheat giving you the situation you have here.
You have to account for this change however you can- while things can change radically the clump of data usually stays the same if it is just a translation (it might have shifted up or down or might have been broken up into a few sections) so you can use the old
cheats to your advantage when building new ones or you can just make a new cheat (get some ore scan the ram, use some ore but nothing/little else, scan the ram again, use some more scan the ram again- you should now be able to tell what location holds the ore and direct your
cheats at it.
Your only problem might come if the game has cheat protection (various methods I will avoid speaking about for now)- I have not heard of too much in Zelda games (unlike pokemon) much less it being used extensively on the GBC but first party games are more likely to see it.
http://nocash.emubase.de/pandocs.htm#gamegeniesharkcheats has what codes are made up as if you need that (you probably have a gameshark/action replay type device rather than a game genie).
