Echelon Series 6000 Chip databook - Manual (Page 83)

The application image checksum covers the application code in both the Application Resident
Code and Constant Data areas. The default behavior is that an application checksum error
causes the device to go to the applicationless state. Application read/write data residing the
Application NVM area is not checksummed.
No checksum is computed if the device is in the applicationless state.
Upon detecting a checksum error, the reset process forces the appropriate state and logs an
error in the error log. A checksum must fail twice during reset processing for it to be
considered in error. If the application checksum is bad, and no application recovery options
are set, an application checksum error is logged, and the device state is changed to
applicationless.
Series 6000 Chip Data Book 71