A U.S. appeals court rejected Apple’s attempt to persuade it that security company Corellium Inc. violated its copyrights by emulating its iOS operating system in order to assist researchers in discovering security weaknesses in Apple products on Monday.

According to the 11th U.S. Circuit Court of Appeals, Corellium’s reproduction of Apple’s system was legal under the fair use provisions of the U.S. copyright code, advancing science by facilitating crucial security research.

Requests for comments on the choice were not immediately answered by company representatives.

Florida-based With the help of Corellium’s software, users may run iOS on non-Apple devices and analyze and alter the operating system in ways that make it easier for security researchers to look for flaws. In 2019, Apple filed a federal lawsuit against Corellium in South Florida for copyright infringement.

Prior to initiating the complaint, Apple made an unsuccessful attempt to purchase Corellium for close to $23 million, according to the appeals court.

In 2020, the district court rejected Apple’s arguments regarding Corellium’s iOS simulator. In 2021, Apple appealed.

The 11th Circuit determined on Monday that Corellium used iOS fairly and added additional features to its software that enable security researchers to “do their work in a way that physical iPhones just can’t.”

Apple claimed that Corellium merely repackaged iOS in a different format for financial gain, damaging the market for its operating system and its security-research initiatives. This claim was dismissed by the appeals court.

Corellium “opened the door for deeper security research into operating systems like iOS,” according to the circuit court.

The appeals court remanded the case to the district court so that it can determine whether Corellium violated the copyrights for Apple’s wallpaper and icons or whether it assisted in infringement by third parties.