A tethered jailbreak modifies a mobile device to bypass some platform restrictions, but it depends on an external trigger-typically a computer and a jailbreak tool-to start the modified state again after the device reboots. Without that step, the device may not boot normally or the jailbreak may no longer be active, depending on the method.
This dependency limits persistence but does not make the device trustworthy. In an attack or security test, a tethered jailbreak can demonstrate a weakness in controls such as code signing or the boot chain, while requiring physical or computer access to reactivate after restart. Defenders should not treat rebooting alone as proof that a device is clean; they may need to verify its integrity, management status, and software state before relying on it.