Engineer Explains How Apple Secretly Fixed The iPhone 4's Antennagate Disaster

Apple's first major iPhone controversy came 15 years ago with the iPhone 4. At the time, users complained that the device would completely lose signal depending on how they held it, a problem referred to as Antennagate. After initially suggesting people were simply holding their phones the wrong way, Steve Jobs eventually offered every iPhone 4 owner a free bumper case to mitigate the issue. However, it was actually iOS 4.0.1 that quietly fixed the problem. To this day, it's remained unclear how Apple managed to resolve the issue without launching a global recall.

While a year later the company redesigned the antenna in the stainless steel frame of the iPhone 4S to put an end to the issue, an engineer has finally uncovered the truth behind that mysterious fix. Believe it or not, it came down to a 20-byte patch. Here's what happened back then, and how Apple actually fixed the issue for iPhone 4 users with a small software update.

In an X post, engineer Sam Henri Gold (via Macworld) revealed that the fix for the iPhone 4's Antennagate in 2010 came down to just 20 bytes of code. By reverse-engineering the firmware of iOS 4.0 and iOS 4.0.1, he discovered the precise changes Apple made. Essentially, Apple had miscalculated the iPhone's actual signal strength. The device often displayed four or five bars when reception was much weaker. Therefore, when holding the iPhone, the signal appeared to drop dramatically, from five bars down to two, making it seem like there was a major antenna flaw.

Apple corrected this by adjusting the values to better reflect real signal strength. That meant users saw fewer five-bar readings, but also experienced fewer drastic drops. The chart above shows the difference between Apple's original signal calculations and the actual readings.

The company even tweaked the height of the lower bars to make them more visually balanced. Still, the iPhone 4 did have a genuine antenna issue, and while Apple lessened its impact with a software update, it wasn't until the following year's iPhone 4S that Antennagate truly became a thing of the past.