If you use rgn tool 0.87 and if you modify pk_files66.zip and add it back to gcd you will have pk_files66.zip (but this work only with 0.87)
I have the same problem with kenwood when i try to modify pk_files66.zip and turboccc add this function in v0.87

p.s.
why you dont try flash with latest FW 4.50?