jailbreaks are currently described as semi-tethered. meaning a jailbreak app must be ran after a phone has booted. your phone stays jailbroken as long as it do

jailbreaks are currently described as semi-tethered. meaning a jailbreak app must be ran after a phone has booted. your phone stays jailbroken as long as it does not power down. it is functionally untethered. as the app that jailbreaks the phone persists through reboots. there are firmware restrictions where these methods work however.