Thanks for the information, I just got an e-notification about a new 46xxsettings.txt file. Not sure if this will help or not. So FYI only.
https://support.avaya.com/css/appman...Downloads_Page
The 46xxsettings.txt file is used to specify certain system parameters. It is used by all 1600, 16CC, 3600, 4600 and 9600 IP & SIP Telephones. The latest version of the 46xxsettings.txt file has been updated to include new parameters used by the 1600, 16CC, 3600, 4600 and 9600 IP & SIP Telephones.
IMPORTANT: There are TWO 46xxsettings.txt files for these products. Make sure you download and use the correct file for your product and release.