Restore is the only option here. Data will be lost. Take a look at this Apple Support article: If you forgot the passcode for your iPhone, iPad, or iPod touch, or your device is disabled - Apple Support
"On Sunday, March 20, 2016, an outside party demonstrated to the FBI a possible method for unlocking Farook’s iPhone. Testing is required to determine whether it is a viable method that will not compromise data on Farook’s iPhone."