See mios_pic18f4685 for a description of the Microchip.
If anyone adapts MIOS and the Bootloader and certain Application Settings to this Chip, it would be kind to document it here.
Note: PIC18F4685 and PIC18F4682 are not 100% binary compatible to PIC18F452. RAM from 0x60-0x7f is not directly accessible. BANKED accesses have to be used instead.