STEP 1 - UNZIP THE DOWNLOADED ROM. MAKE SURE ITS MT6582 ROM.
STEP 2 - TAKE BOOT.IMG FROM STOCK ROM AND UNPACK IT AND TAKE ITS KERNEL AND UNPACK THE DOWNLOADED ROM BOOT.IMG AND REPLACE THE KERNEL FROM STOCK IN IT AND REPACK IT.
STEP 3 - TAKE FIRMWARE FOLDER FROM ETC/FIMWARE FROM STOCK ROM AND REPLACE IT IN DOWNLOADED ROM.
STEP 4 - ZIP THE FILES AND FLASH.