The 20 bytes of code that fixed Antennagate in the iPhone 4

Ah, 2010. The year when Apple launched the iPad, but the limelight was stolen by something else entirely: Antennagate. Soon after the launch of the iPhone 4, users discovered that when they held the phone in a typical grip for a phone call, the number of bars shown for signal strength immediately dropped dramatically.

Apple responded in a number of ways, including Steve Jobs famously suggesting that users were holding the phone wrong, but the issue was resolved by changing just 20 bytes of…