Yealink SIP-T48S Rebooting, Updating Firmware, Factory Reset

If your phone is malfunctioning or require updates you or your phone system administrator may want to perform one of the following:

Rebooting - this will bring the phone back to the its last configured state. It is also required sometimes when TeleConsole settings have been updated such as after modifying TeleConsole BLF settings.

Updating firmware - firmware is the software that loads when the phone is started and controls its functionality. Updating it to a newer version when one is released may resolve or improve phone performance issues. 

Factory reset - this erases the current configuration and apply the original configuration the phone was shipped with from the factory.  It is possible to erase just the phone configuration, just the the user customized data, or both.

Rebooting Your Phone

In most cases this can be attempted when your phone malfunctions without much concern. If this fails to solve the problem you can attempt the other two methods

To reboot the phone via web user interface:


  • Click on Settings>Upgrade.

  • Click Reboot to reboot the IP phone.

    The reboot may take a few minutes

Upgrading the Firmware

Firmware files can be downloaded from the Yealink support portal. The downloaded file should be stored on a computer or network location that can be accessed by the web user interface. 

You can check the current firmware version installed on the base or a handset to see if an update is indeed required. 

To check the firmware version via phone user interface: 

  • Press    or tap  >Status.

  • The screen displays status information of the phone in various tabs. The firmware version is under the General tab along with the IPv4 or IPv6 status and MAC address. 

    You may need to provide information from this or the other tabs, besides the firmware version, to your phone system administrator for additional phone support or maintenance.

To check the firmware version via  web user interface:


  • Access the phone via the web user interface as explained here.

  • The firmware version is the first item found under the Status>Status path on the first page of the web user interface.

    Other information is show here including IPv4 or IPv6 status, network configuration, and account status. You may need to provide some of this information , besides the firmware version, to your phone system administrator for additional phone support or maintenance.

To upgrade firmware via web user interface: 

  • Click on Settings>Upgrade.

  • Click Browse to locate the required firmware from your local system.

  • Click Upgrade to upgrade the firmware.

    The browser pops up the dialog box “Firmware of the SIP Phone will be updated. It will take 5 minutes to complete. Please don't power off!”.

  • Click OK to confirm upgrading.

Factory Reset

This is only recommended after you have tried the other troubleshooting suggestions. Since two of the options here will delete all your personal configuration settings, it is advisable to have your phone system administrator backup your personalized settings before proceeding.

Three ways to reset the phone:

Full Reset - all configurations and the user data on the phone will be reset.

Config Reset - all configurations (e.g., account, call history) set on the phone will be 


Userdata Reset - all custom data (e.g., ring tone) set on the phone will be reset.

To perform factory reset of the phone via phone user interface:

  • Tap >Advanced (default password: admin) >Reset to Factory.

  • Tap the gray box of the Reset Option field, and then select the desired reset option from the pull-down list.

  • Tap the Reset key.

    The touch screen prompts the following warning:

  • Tap OK.

    The phone begins resetting. The reseting process may take a few minutes. Do not power off until the phone has started up successfully.

  • When the resetting is done the touch screen prompts “Welcome Initializing…Please wait”.

Did you find it helpful? Yes No

Send feedback
Sorry we couldn't be helpful. Help us improve this article with your feedback.