failbreak

The term failbreak refers to a jailbreak that cannot be released due to a variety of reasons, which makes it a fail to an extent. This term came about when chpwn showed a screenshot of his new iPhone 5 running Cydia shortly after its launch on September 19, 2012. Shortly afterward, usage of this term picked up, and on October 19, 2012, planetbeing tweeted that he upgraded the "failbreak" with a kernel exploit so that tweaks actually work on the iPhone 5, to make it "almost a full tethered jailbreak."

For the most recent "failbreak" (for iOS 6), the issue preventing its release is that it requires an Apple developer account and developers are under an NDA.

failbreaks

• iOS 4.2.1 (Jailbreak Monte)
  • Access to iOs 4.2b3 beta for device
• iOS 6 on A6
  • Apple Developer account required
  • Developers under NDA

References

• @chpwn with jailbroken iPhone 5
• @pod2g confirming chpwn is trustable
• @chpwn mentioning the term the first time
• @planetbeing on "the kernel exploit"