Legend of Zelda Four Swords 25th Anniversary Edition Corrupted Save File

[LeafAce]

So using godmode9, I accessed TWL NAND filesystem to edit my zelda four swords character name using a hex editor. I really didn't like the name I put there years ago, so I wanted to change it. I found the 'public.sav' file and opened it in GM9's hex editor. There were two instances of my character name (there is only one save file in my dsi game). I changed one letter in both those instances to the same letter, saved it, loaded Four Swords, and it says it was corrupted. I changed the hex file back to what it was originally, and it loaded fine.

Question: How do I get around this so I can edit my dsiware save without it getting corrupted? Also why does this happen?

 

[tastymeatball]

This is because the save file has a checksum
The checksum are the 4 bytes you will find in front of the word S4FT which you will find 1 for every save file. The first one is for some sort of global save block. The remaining 3 are the 3 save files (if the file is empty you will instead find the word INIT). The 5th you will find just marks the start the start of global save block and therefore doesn't have a checksum in front of it.