Well, normally I would say the latest, such as X3_3294. However, mine only works with 2914 for some reason (-: and no it's not pins 13/14

. Give 3294 a shot and if doesn't work then try 2914. Also be sure to use the right BIOS file as there are two in each rar. One if for XBOX v1-5, the other is for 1.6+.