Not sure about the cart, but I just put English Roms into my Demon Front PCB
Here's a patch by request for DDP2 to force Korea region.
Apply to 'v102.u8' from MAME 'ddp2.zip' and burn to an M27C160 EPROM.
Let me know how it works for you @yonggarri and anyone else that may find it helpful - cheers!
As always xdelta UI can be found here: https://www.romhacking.net/utilities/598/
In Japanese version you start with 3 bombs and in this version you start with 5.What's the deal with changing DDP2 from JPY to Korea other than the language change? Modified difficulty?
(Apologies if mentioned above already.. I looked up but couldn't see any answer in a handful of pages!)