Yealink VC400 Administrator's Manual page 289

Upgrade firmware
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Configure some features need to take effect after a reboot
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You can reboot the system in the following ways:
Long press the power button on the VC400/VC120 codec.
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Select Menu->Advanced (default password: 0000) ->Reboot & Reset->Reboot, and

then press
Login web user interface and click on Setting->Upgrade->Reboot, and then click

Confirm.
To avoid corrupting the system, you should not unplug the power adapter from the system to
power off the system.
Why does the system fail to upgrade?
Ensure that the firmware is different from the firmware currently in use.
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Ensure that the downloaded firmware applies to the system.
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Ensure that the system is powered on normally, and the network is available during the

upgrade process.
When upgrading firmware via web user interface, ensure that the web user interface is not

refreshed or closed during the upgrade process.
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Troubleshooting
273