Here's another little trick for you guys that have a G6...
If you have a G6 and played part way through the Japanese version, you can use that save on this new (U) dump! To do this:
1. Take your original japanese .0 save off your card and place it on your desktop.
2. After you put the new rom onto your G6, look in the NDS folder and see what your new US .0 save is named.
3. Name your original Japanese .0 file on your desktop the EXACT same name as the new US .0 save on the G6.
4. Overwrite the .0 save on your G6.
5. Boot up and enjoy, you should have everything you had from your Japanese game save.
Side note: make sure that you don't have a Castlevania save sitting in your sram prior to overwiting the rename, as that will just over write what you just over wrote. What the hell... did that even make sense?
Just boot your G6 prior to doing all the above steps, so it boots clean once you change your .0 file and you should be all cool.