3.2.2 Region Reconfiguration

ECC Error Reporting describes how the region settings are copied from the region descriptor in the configuration bits/fuses into registers on Reset. Each region has a lock/unlocking mechanism. From a locking perspective, a region can be from three states.

Table 3-1. Lock State
Lock State	Behavior
Locked	Region registers cannot be modified. They can be unlocked via the unlock sequence.
Unlocked	Region registers can be modified.
Locked until reset	Region registers cannot be modified. A region cannot be unlocked until the next Reset occurs.

All regions default to the Locked state. The firmware region type is the only region type that can be unlocked and, thus, the only region type that can be reconfigured at run time.

Table 3-2. Flash Region Type
Flash Region Type	Can Be Unlocked?
Immutable Root of Trust (IRT)	No
OTP	No
Firmware	Yes

The ability to reconfigure a region’s permission at run time and then lock these settings until Reset allows systems to implement more complex permission and protection schemes discussed in Security Use Cases.