I noticed that the linker files for both the TWR-K64F120M and TWR-K60F120M have the "rom" section set like this:
rom (RX): ORIGIN = 0x00000420, LENGTH = 0x0007FBE0 /* Code + Const data */
I've been changing this line to make the full flash capacity available.
rom (RX): ORIGIN = 0x00000420, LENGTH = 0x000FFBE0 /* Code + Const data */
Is this a good thing to do or should I make an additional "rom" section?