Ratchet Check for NVIDIA Owned Software Components

For NVIDIA owned software binary, the true hardware ratchet level is obtained by taking sum of the NVIDIA owned ratchet level and OEM owned ratchet level.

This combined ratchet level is then compared with the software ratchet version of the binary.

The ratchet check is both self-enforced and loader enforced.

• Self-enforced ratchet check:
  • This check resides within the same code that the rollback is trying to protect. In other words, the binary that is executing performs its own ratchet check.
  • It is basically a self-check to ensure that older binary does not continue execution on newer systems.
• Loader enforced check:
  • This check happens before the binary is even executed.
  • The ratchet version of the binary being loaded is available as part of its boot component header, making the loader capable to fully investigate the rollback status.

If any ratchet check fails in Boot ROM, recovery mode is triggered.

If any ratchet check fails in MB1, then either boot with alternate chain is triggered or the target is put into recovery mode, depending on the soft fuses for boot chain options.