I’m with Particleweave. That thing, even cleaned up, is most likely done. IMO with that much visible corrosion, (that was wet for awhile) no telling how bad it is at a micro level. Given that is completely necessary for the entire car to function, it’s time for a replacement. Give these guys a call/email.
Porsche 996 & Boxster ECU Test and Repair, Immobilizer Removal, and Performance Tuning Upgrades - Specialized ECU Repair