For a long time, Apple has been getting a lot of criticism for its almost fanatical initiative to keep the iPhone locked and maintain almost total control over virtually every iPhone feature. Even efforts to jailbreak the phone have been met with intense hostility, with legal action and even crippling updates to punish dissenters.

Now it seems that Apple has been slowly adapting a more subtle method and this time it is all about screwing your iPhone, literally. In this case, the company has been replacing the screws on the iPhone 4s that come in for servicing and replacing them with tamper-proof screws, with the hope of preventing unauthorized meddling.

Experts claim that Apple has been changing the screws as far back as November. Once a customer takes an iPhone 4 for servicing, the staff at Apple will replace the Phillips type screws with Pentalobe type screws, without informing the customers.

The reason behind this seems to be the battery. Users can have their batteries replaced free of charge if their phones are under warranty. Otherwise, Apple charges $79. By locking out the iPhone, Apple will seek to maintain its grip on the sales of iPhone batteries. The downside in all of this is the negative impact on consumer choice. The limitations imposed on the software of the iPhone are now being slowly applied to the hardware as well.