🔴 This project is still a work in progress as there ares only my test results available yet!
The JED configuration in this project enables the original 1MB Kickstart ROM option seen on A4000T mainboards. This option is also added to my modified versions of the A4000D mainboards.
To make use of this option you need a GAL like the ATF16V8B-10 for the unpopulated component P155 (BIGROM). Use the JED file in the logic folder to program this GAL. Then you need to remove the 2 resistors R155A and R155B and solder a PLCC-20 socket onto the board and insert the GAL.
To create 1MB Kickstart ROMs for the latest Kickstart version I use capitoline. The steps to create a 1MB ROM are described here http://capitoline.twocatsblack.com/index.php/1mb-hyperion-rom.
The 1MB Kickstart will be 2 parts, 512k at $00F8.0000 and the extension at $00E0.0000. If there is no specific profile for the A4000(T) BIGROM available, you can use the generic version and place the normal $F8 and the extension $E0 and create this combinded Kickstart for at least 2x 512K EEPROMS/Flash.