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Line 33:
Line 33: − − ==== Fuse coherency ==== − − Unit type is computed from data from a fuse. It must be either 0 (non-retail) or 1 (retail). If it's neither, 2 will be returned by the function, and the check will call panic. − The bootloader verifies a lockdown fuse counter to prevent downgrading. A 32-bit lockdown value at fuse offset 0x1E4 is checked. If too many fuses are burned the bootloader will panic. If too few are burned, the bootloader will program the expected number of bits and force a reset. The expected lockdown value differs between unit type 0 (non-retail) and unit type 1 (retail).+ − − {| class="wikitable" border="1" − |- − ! System version − ! Expected number of burnt fuses (retail) − ! Expected number of burnt fuses (non-retail) − |- − | 1.0.0 − | 1 − | 0 − − | 2.0.0-2.3.0 − | 2 − | 0 − |- − | 3.0.0 − | 3 − | 1 − |- − | 3.0.1 − | 4 − | 1 − |}
no edit summary
* The entrypoint of stage 2 is computed.
* The entrypoint of stage 2 is computed.
* The stack is pivoted to a secondary stack, the main stack and the key area are cleared, and stage 1 jumps to stage 2's entrypoint.
* The stack is pivoted to a secondary stack, the main stack and the key area are cleared, and stage 1 jumps to stage 2's entrypoint.
==== Downgrade check ====
==== Downgrade check ====
See [[Fuses#Anti-downgrade|Anti-downgrade]].
|-
==== Panic ====
==== Panic ====