The processor type is controlled which board you select, which is
controlled by the boards.txt file under {arduino_installdir}/hardware
So you are saying that your glcd sketch worked on the 1280 and when you swapped out the 1280 chip
for a 1284 chip it no longer works?
I have not looked at the Arduino pin mapping for the 1284/1284p but
If the 1284 pin mapping is exactly the same as the 644 then what you did should work.
(It looks like you cloned the 644 pin mappings for your 664 and 1284 pin mappings)
Getting the pin mapping correct (it must match what the core code uses)
is critical as the glcd library does not use the Arduino core functions
like digitalWrite()/digitalRead() as they are too slow.
The best way to diagnose this is to run the diag sketch and see what pins the library is using.
Look at the serial output and you will see the port and bit numbers being used for each pin
in the configuration file.
If they don't match the port and bit numbers for the Arduino pin on a 1284 (or whatever AVR you are using)
then the pin mapping you created is incorrect.
The diag serial output will show everything that is needed to diagnose any potential
pin mapping issues.
--- bill