
iBoot alternatives
iBoot is a stage two bootloader for all Apple products. This replaces the old version BootX with improved authentication performed at the boot chain. The boot process starts with running code stored in secured UEFI boot ROM for macOS. The first stage, as usual, performs two steps. The first one is the initialization of system hardware and selecting the OS in order to run on the UEFI component. And for iOS, the process initializes by running the device Boot ROM code in the system with S processors or early A-series chips up to A9.
It usually loads with the low-level bootloader. The newer chips, the Boot ROM loads iBoot by itself and then proceed to load the actual operating system along with the kernels. The security improvement step works if the iBoot fails to load and verify the iOS, which then jumps to DFU mode.










