During a network gateway firmware update, an error code appeared on the unit's user interface. Now what?

During firmware upgrades, the network gateway stops communicating with the user interface. As a side effect, the user interface will display an error code. When the network gateway is fully upgraded, communication will restart and the error will disappear from the user interface.

BRP069A6x:

It’s expected  that error code “U8-01” will appear on the user interface temporarily.

DRGATEWAYAA:

It’s expected that error code “U4-66” will appear on the user interface temporarily.