Hi, looooong-time lurker here (it's my first post on forums since joining in 2009, sooo... yea :/ )
If you decompress the rom (with, say, DSLazy or similar thing), look in these folders:
"data/E/G"(microgames),
"data/E/R"(records),
"data/E/M"(comics aka manga in JP).
First 256 bytes are an...