Problems Programming Auxiliary Space Using PICKit™ 3 Programmer-To-Go
There is a program size limitation on the PICkit™ Programmer-To-Go (PTG). The PICkit 3 PTG does not support memory sizes larger than 512 KB. The partition of the PTG image and mapping structure allows for both PGM and AUX to co-exist as long as total memory usage ( including configuration words) is contiguous and does not exceed 512 KB.
Some devices, such as the dsPIC33EP512MU810, do not have contiguous configuration memory and are not supported by PTG even though they have 512 KB of programmable memory.