Issue

When IP Phones enter a reboot loop, attempt to “upgrade”, fail, then reboot again, or
When IP Phones enter a reboot loop, attempt to “upgrade”, fail with “FW authentication failure”, then reboot again

Environment

Avaya CS1000

UNIStim 5.0 or earlier

Avaya IP Phone 1100, Avaya IP Phone 1200

Cause

UNIStim firmware is digitally signed.

Signature has an expiration date.

UNIStim versions prior to 5.0 had shorter expiration dates.

New IP Phone hardware will not load firmware with expired signatures.

Source: http://downloads.avaya.com/css/P8/documents/100152833

Solution

Use UNIStim 5.1 or later firmware.

Avaya has applied a digital signature with a 10 year expiration date to UNIStim 5.1 and later.

UNIStim 5.5.1 (C8T) released in Aug 2013.

I updated my Google drive table of UNIStim firmware releases.