Detroit DDEC2 to DDEC3/4

[Doops22]

I’ve got a KW w900 with a DDEC3 12.7 in it that decided to throw a rod through the block. I have an older parts truck with a DDEC2 12.7 in it that I am going to replace it with. I don’t care about losing power or anything like that I just need it to run. I’ve seen the conversion kit from Detroit to update a DDEC2 truck to 3/4. I’ve got all of the sensors wiring and intake off the blown motor so my only issue is the ecm. Is it possible to have my DDEC3 ecm reflashed to read the different bull gear in the DDEC2, and if so any recommendations on who? If not do I need to buy the ecm from the conversion kit?