Joukey Gm Checksum Plugin [ 480p ]

Let’s fix a real-world example: a patched ROM of Sonic 3 & Knuckles that crashes on Kega Fusion.

function save_game(data_struct) 
    var buff = buffer_create(1024, buffer_grow, 1);
    buffer_write(buff, buffer_string, json_stringify(data_struct));
    buffer_save(buff, "save.sav");
    checksum_append_and_save("save.sav", checksum_sha256);
    buffer_delete(buff);
function load_game() 
if (!checksum_verify("save.sav", checksum_sha256)) 
show_error("Save file corrupted!", false);
return undefined;
var buff = buffer_load("save.sav");
var json = buffer_read(buff, buffer_string);
buffer_delete(buff);
return json_parse(json);

If you are part of a fan translation team patching a 4-megabyte RPG, you will apply dozens of patches over months. Instead of fixing the checksum after every patch, use the Joukey plugin on the original clean ROM first. Create a "base" ROM with checksum disabled, then apply your translation patches to that file.

Let’s fix a real-world example: a patched ROM of Sonic 3 & Knuckles that crashes on Kega Fusion.

function save_game(data_struct) 
    var buff = buffer_create(1024, buffer_grow, 1);
    buffer_write(buff, buffer_string, json_stringify(data_struct));
    buffer_save(buff, "save.sav");
    checksum_append_and_save("save.sav", checksum_sha256);
    buffer_delete(buff);
function load_game() 
if (!checksum_verify("save.sav", checksum_sha256)) 
show_error("Save file corrupted!", false);
return undefined;
var buff = buffer_load("save.sav");
var json = buffer_read(buff, buffer_string);
buffer_delete(buff);
return json_parse(json);

If you are part of a fan translation team patching a 4-megabyte RPG, you will apply dozens of patches over months. Instead of fixing the checksum after every patch, use the Joukey plugin on the original clean ROM first. Create a "base" ROM with checksum disabled, then apply your translation patches to that file.