In the old 1.5.7 version of the IDE there used to be an 'avr' and 'sam' folders under 'arduino-1.5.7\hardware\arduino'.
I can't seem to find these folders under the new 1.6.2 IDE. I went into board managers and downloaded the package for the Due. Still no luck. Can someone please point me to where these folders are. For many of my work I used to go in and modify parameters in those files. Need to make some changes in the new IDE.