Get a Bentley manual to explain how it works. Randomly replacing parts without a BMW diagnostic tool such as the GT1, Autologic, or BT tool will only lead to frustration. No one here can help you because there is no way to do this over the Internet. Take the car to a BMW specialty shop if you cannot learn everything there is to know about the N54 boost control system and how to diagnose it.
Otherwise you may be stuck in transport mode. You don't need a JB4 or Procede to deactivate it. You will need a dealer or other shop with a GT1 or Autologic, though.
E92 335i/6MT Dinan Stage 3: intercooler, oil cooler, intake, flash, exhaust, LW dual-mass flywheel.
Vishnu PWM methanol custom trunk mount, Diffsonline 3-clutch Salisbury custom diff, Ohlins Road and Track coilovers, Vorshlag camber plates, much more...
E28 M5 w/ buncha stuff, R171 SLK350