failbreak

The term "failbreak" refers to a jailbreak that cannot be released to the general public, which makes it a fail to an extent. There are a variety of reasons a jailbreak will become a "failbreak." 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."

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"