Mate you don't need to go buying an ECU to fix such a small inconvenience! Buy yourself a HKS actuator as described by Charlotte, and set it below 0.8 bar. What also helps massively is to port the wastegate on the turbo, it will probably have a crack in there like most ct9s but it'll be fine. My car running like that for a few months perfectly at that boost level and didn't hit fuel cut, and I had similar mods