If Mozilla ever does make an iOS version of Firefox, it won’t just be a skin for Safari. Jay Sullivan, the company’s vice president, told an audience at SXSW that Firefox won’t be coming to Apple’s platform until Cupertino relaxes its stance toward third-party browsers. The news was reported by CNET.

As it stands, all third-party browsers on iOS render websites using Apple’s UIWebView component, while Apple itself uses a different, faster JavaScript rendering engine called Nitro. Apple doesn’t expose the Nitro engine to third-party developers, and it doesn’t allow them to write their own, giving Safari a built-in speed advantage against other browsers on the platform, including Google’s Chrome. That just won't do for Firefox, says Mozilla, which wants to bring over its own code, like the new IonMonkey engine found in the desktop and Android versions of Firefox. Mozilla isn't swearing off the platform completely, though. Last year, the company showed off an iPad browser prototype codenamed Junior that used Apple's UIWebView, saying ""there are a lot of reasons we should be on iOS even though we can't bring our rendering engine there."

The situation echoes the problems Mozilla is facing on Microsoft’s Windows RT, which prevents third-party browsers from accessing Win32 APIs. As a result, it’s prevented from building its own fast JavaScript engine for the platform, or offering the same kind of security and stability that it can on other desktop platforms like Windows 8 or OS X.