These BOM calculations are inherently flawed because there's no way a third-party can know what it actually costs to develop and produce the many custom parts i

These BOM calculations are inherently flawed because there's no way a third-party can know what it actually costs to develop and produce the many custom parts in the phone. The A6 chip, for instance, may incorporate standard ARM cores and chips, but it was developed using a custom internal design process. Similarly, the new combined-glass-and-digitiser screen must have involved a fair bit of R&D spend and changes to the manufacturing process before it could even be produced in the required volumes. Apple consistently quotes a 30-40% margin (not gross margin) on its iOS range, which is not unreasonable considering the additional costs it sustains in developing value-added services like iCloud and having a good support setup in place. Looking at the court records that were unsealed recently I honestly don't think the real iPhone BOM has changed that much from model to model, with the exception that it's hugely profitable for Apple to continue to sell the older model (now the 4S) with cheaper-to-produce components.