HP 8920B Programmer's Manual page 651

Non-Recoverable Firmware Error
The non-recoverable firmware error is very important. It appears when an unanticipated
event occurs that the Test Set's firmware cannot handle. The message appears in the
center of the Test Set's display and (except for the two lines in the second paragraph) has
the following form:
Non-recoverable firmware error. Please record the 2 lines of
text below and contact Hewlett Packard through your local
service center or by calling (800) 827-3848 (USA, collect) and
asking to speak to the 8920A Service Engineer.
'Address error exception'
at line number 0
To continue operation, turn POWER off and back on.
Follow the instructions in the message.
Unfortunately, you will not be able to recover from this condition. You must switch the
Test Set off and back on. When you rerun the test where the Error Message occurred, it
may not occur again. If it does reappear, it would be helpful to HP to record exactly what
the configuration of the instrument was when the error appeared and contact HP.
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