I'm trying to customize the core to a sibling folder to the genuine core folder and be able to select the correct board from the "boards" menu in the 1.6.5 IDE.
I'll assume you'll be familiar with this process and leave out the play-by-play.
I successfully got it to work without any difficulty. As I understand it, the key to making this work is editing only two lines .name and .build.core. So, I copied and pasted the Mega256 parameters in the boards.txt file and altered the two lines. Booting the IDE and checking the "boards" menu, my new board name is there. The problem is, the old name is NOT there. Is it no longer possible to have dual core configurations for the same physical board?
If it's not clear what I'm talking about, this link should explain it.