A meter that has been upgraded to firmware version 3.0.0 or later cannot be downgraded to an earlier firmware version.
LOSS OF DOWNGRADE CAPABILITY
Do not upgrade to firmware version 3.0.0 or later if you need to downgrade the meter in the future.
Failure to follow these instructions can result in loss of firmware downgrade functionality.
After upgrading the meter firmware to v2.2.1 or later, the previous upgrade agent cannot be re-applied.
Meter restart is required.