MC Studio bootloader works great with xtal. But, there is always a but, when I load 18F4620_04.hex using meProg U2 with INTRC(INTIO2) configured then MC bootloader no longer functions, because (I think) there is no way (with my skill set) to set the bootloader speed at 1 MHz or set the target at 4 MHz with OSCCON.

This important because we want to simplify hardware in the field at scale and not use external crystals, allow code upgrades, and watch/modify data flow using a notebook serial port. It must be dirt cheap. The solar tracking code will be open source for places like India and China, posted in user-friendly BASIC. They hopefully will only need PBP + MC Studio Plus for local integration.

I saw in the forum a patch for 16F****. Is there something for 18F4620 using internal oscillators, perhaps working with PIC internal OSCCON default 1 MHz, or a method to smuggle in a 4 MHZ OSCCON ?

_OSC_INTIO67_1H