You have two methods to use:

METHOD 1:
a). Borrow a time machine.
b). Go back in time.
c). Get source code.
d). Buy stocks and place bets.
e). Return to present with soruce code.
f). Collect investment earnings.
g). Pay for time machine rental

METHOD 2:
a). overwrite partial new code in himem
b). overwrite a redirect link to himem
c). new code uses movc op to read bytes
d). read bytes shot out serial link.
e). capture memory dump at serial link.

Caveats. Doing A & B are tricky and depend upon chip vendor. Some are pathetically protected and recently upgraded to Rx2 :) to correct this. I want talk about A & B further. If you CAN achieve this process, you should consider no longer using this uC vendor because they cannot protect your code.

All documentation suggests A & B can not be done. Those that achieve it, usually keep it to themselves.

Personally, I wrote to Philips Semi about a security hole I felt that I had spotted. They denied something I didn't suggest and pulled the Rx+ off the market and delayed the release of the Rx2 for 9 months. Probably a coincidence. :)

aka j