Hello.
This ticket was derived from another ticket.
I have a few questions about hardware-based downgrade protection.
- About the Downgrade Protection of the Network Core
Even with Downgrade Protection enabled, the Network Core is still downgradeable.
However, version mismatches between the App Core and the Network Core should be avoided.
If you have any ideas on how to resolve this, please let me know. - About the monotonic counter
Is there a way to retrieve the current value?
I am assuming it will be displayed on a PC serial terminal or a smartphone app. - About Image Swap
It seems that when the update count reaches the value of SB_CONFIG_MCUBOOT_HW_DOWNGRADE_PREVENTION_COUNTER_SLOTS, the Image Swap of the App Core is performed every time the software is rebooted.
Is this the expected behavior?
The logs during the update and reboot are as follows:
monotonic counter < SB_CONFIG_MCUBOOT_HW_DOWNGRADE_PREVENTION_COUNTER_SLOTS
Update
Reboot
monotonic counter = SB_CONFIG_MCUBOOT_HW_DOWNGRADE_PREVENTION_COUNTER_SLOTS
Update
Reboot
Thanks for reading.
a.da