Put the firmware on an SD card and the encrypted project in the root directory. Then it needs a script in TRIOINIT.BAS on the SD card:
IF INT(VERSION * 10000) <> 20304 THEN FILE "LOAD_SYSTEM" "MC405_20304"
PROJECT_KEY "MyKey"
FILE "LOAD_PROJECT" "project_name"
Substitute the required frimware, project key and the project name.