Unprogramming recoverable?

Hey to everyone, I had pops and bangs programmed for my Suzuki Swift a few months ago. Shortly after that, the engine control light went on (“catalyst efficiency”), so I changed the cat and the lambda probe. Now the lamp lights up again, and the pops and bangs never worked properly. I suspect there’s still a faulty programming in the control unit. Could you reset the control unit to serial status? Could the wrong softw Are the cause, or is the new cat already defective? What would the reset cost? Or can I reset the ECU myself by disconnecting the battery? Thanks for your help Lg jan