Overview

• Gold’s analysis of iOS 4.0.1 identifies a 20‑byte patch in the CommCenter lookup table that smoothed the thresholds used to convert signal strength into bars.
• The original iOS 4 formula was overly optimistic, so bars often showed 4–5 before dropping abruptly when the phone was gripped, a perception the new thresholds reduced.
• Apple had said in 2010 that its bar‑display formula was wrong and adopted an AT&T‑recommended approach, which iOS 4.0.1 implemented.
• The update also increased the on‑screen bar heights, making low reception indicators less alarming to users.
• Apple supplemented the software change with free bumper cases at the time and later repositioned antennas in the iPhone 4s, effectively ending widespread complaints.