Can't activate Cisco 504G and 303 Phones due to firmware not compatible with the new Certificate.
- Cisco 504G and 303 Phones
Upgrade firmware to 7.5.7 by following these steps:
The certificate for legacy Cisco phones has expired and unfortunately the new Certificate is not compatible with f/w 7.5.2b.
If the Cisco link is inaccessible a back up of the Cisco tool can be downloaded here
For Cisco phones that have already been activated and are online, no action is necessary
After updating and re-provisioning, phones may take up to 5 minutes to respond.