I tried to make my own version of 1.06-RPC1. I checked the difference between 1.05-RPC2 and 1.05-RPC1. Three bytes and checksum were different. Then I searched 1.06 binary to find out same byte-sequences and modified them. The checksum seems to be 16bit integer. I recalculated the checksum.
Then I compared my own version and TDB version. Both are completely same