Checkra1n

checkra1n is a jailbreaking tool for iOS devices that uses the boot ROM exploit known as checkm8 to gain low‑level access to the device. Developed by the AxioμX team (often referred to as axi0mX) and collaborators, checkra1n targets devices powered by Apple chips ranging roughly from A5 to A11, including models such as the iPhone 5s through the iPhone X and certain iPad generations. The exploit is hardware‑based and, because it resides in the boot ROM, is not patchable by standard iOS updates. This enables a persistent opportunity to jailbreak on supported devices.

Because checkm8 is a boot ROM vulnerability, checkra1n operates as a host‑based tool. A compatible computer must run the checkra1n software to apply the jailbreak to a connected device, typically after reboot, which classifies the jailbreak as semi‑tethered. The process installs a jailbreak loader and can configure optional package managers such as Cydia or Sileo to manage user‑land tweaks.

Platform support for checkra1n has been targeted at macOS and Linux environments, with official Windows support not provided in all releases. Users on Windows may run checkra1n via alternative setups that enable a Linux or macOS environment.

History and impact: released in 2019, checkra1n was notable for enabling jailbreaking on a broad range of older devices via a boot ROM exploit. It has since evolved to support additional iOS versions on supported hardware, though devices with newer boot ROMs (beyond A11) are not affected by checkm8 and are not supported by checkra1n.

Limitations and safety: the tool supports a subset of devices and iOS versions, and jailbreaking can void warranties and introduce stability or security risks. Users should back up data and be aware of local legal considerations before proceeding.

See also: jailbreaking, boot ROM exploit, checkm8, Cydia, Sileo.