are supported via other BootROM exploits such as limera1n, alloc8, and SHAtter, going back to the iPhone 3GS.
On certain devices, you can “demote” the bootloader to enable JTAG debugging. This is a very low‑level hardware debugging interface. ipro+pwndfu
Hardware exploits are subject to strict timing parameters. If your exploit fails or gets stuck on "Sending Payload," check the following: are supported via other BootROM exploits such as