UC500.com

I am running Cisco IOS12.4 (11r) XW8, CME Bundle v4.2 on a UC520. I am trying to upgrade the 7965G firmware from SCCP45.8-3-2S to SCCP45.8-4-2S as I am having trouble getting a Plantronics HHC adapter cable working with a Headset. I understand this will only work with SCCP v8.3(3) or higher...............Hence the attempted upgrade. I have downloaded the cmterm-7945_7965-sccp zip from the Cisco site and have used Solarwinds TFTP to get the 8x files within that folder onto the flash of the UC520. However when I configure;

telephony-service

load phone-type SCCP45.8-4-2S

create cnf-files

I find on rebooting the phone it comes up with an error then it defaults back to the original SCCP45.8-3-2S file.
Has anyone seen this before or got any suggestions??