Changes

==== FUSE_SPARE_BIT_5 ====

==== FUSE_SPARE_BIT_5 ====

Must be non-zero on retail units, otherwise the first bootloader panics.

Must be non-zero on retail units, otherwise the first bootloader panics.

On debug units it can be zero, which tells the bootloader to choose from two debug master key seeds. If set to non-zero on a debug unit, it tells the bootloader to choose from two master key seeds (with the second one being the retail master key seed).

On prototype units it can be zero, which tells the bootloader to choose from two pre-production master key seeds. If set to non-zero on a prototype unit, it tells the bootloader to choose from two master key seeds (with the second one being the same as the retail master key seed).

[4.0.0+] This value is no longer used during boot.

[4.0.0+] This value is no longer used during boot.