Why replace 25020 with 93c86 to immo off

[yem22]

Hi all
Im wondring why to immo off some car of toyota
Like corrella. Landcruser
I replace 93c86 with 25020 contain some data
I mean remove old 93c86 and put 25020 eeprom had some data
Thy not share same ground pin
How ecu read that not same type nor circuit
And it start car

[m-o-y]

to find an answer you need to put the 86 data and 25020 data , and car + model ,
because some cars you need to read the main flash and other in eeprom..
so , one of suggestions , try to remove the eeprom only.\
goodluck