Hi,
I did it on the hardware way with a test-clip on the eeprom (see the picture), but you have the unit switched on and the processor in "endless" reset, so that its pins are in a high impedance state.
I used different test clips at the processor seen in the picture, that are connected with a 1k resistor.
Then I used a GQ-4X programmer (choose 93C66B-Device with 16bit NOT 8bit).
So you can read and write the eeprom.
I´m also keen on: Is there a different way to read the constants (via HPIB or serial)?
best regards
Ronny