Apple has lost its bid to revive US copyright claims against Corellium, a security startup that recreates the iOS operating system to help researchers identify vulnerabilities. The 11th US Circuit Court of Appeals ruled that Corellium had lawfully recreated Apple's system under the fair use doctrine of US copyright law. The court said Corellium's software added new features that helped security researchers "do their work in a way that physical iPhones just can't". Apple unsuccessfully attempted to purchase Corellium for nearly$23m before filing the lawsuit in 2019.

The ruling also rejected Apple's claims that Corellium had repackaged iOS in a different format for profit, harming Apple's market for its operating system and its security-research programs. However, the appeals court sent the case back to the district court to consider whether Corellium infringed copyrights covering Apple's icons and wallpapers or contributed to infringement by third parties.