Triggering the Recovery Mechanism by BootROM

The BootROM loads MB1 from the Active Boot Chain.

• If BootROM fails to load the MB1 image in the Active Boot Chain, the sequence is as follows:
  • Switch the Active Boot Chain and set the invalid boot chain to 1.
  • Load MB1 from the next new Active Boot Chain.
  • If a failure occurs again, attempt to load next chain, if supported, or boot into forced recovery mode.
• Soft fuse values are NOT used by BootROM.

Because BR BCT does NOT belong to any boot chain, recovery for this component takes place as follows:

• A single partition is provided for storing BR BCT.
• The partition is shared by both boot chains. The partition contains multiple copies of BR BCT. All copies are identical.
• Each copy is placed at the beginning of the boot storage device.
• The BootROM handles the recovery of BR BCT. If one copy of BR BCT is found to be corrupted, the BootROM proceeds with the next copy of the BR BCT until a valid copy is located. If a valid copy is not located, BootROM resets into forced recovery mode.
• At the time of the system update, each copy of BR BCT is updated to the new version to ensure all copies are at the same version.