Notification: Firmware Upgrade Steps for Users with FQDN Objects (4.39 WK38, 4.55 WK38, 4.60C0)

Zyxel_Charlie Posts: 1,034  Zyxel Employee
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You may encounter device freeze, after upgrading firmware to 4.39WK38 or 4.55WK38, PROVIDED THAT YOUR RUNNING FIRMWARE VERSION IS:





The Symptom:

The firmware listed above is subject to a bug, that when FQDN object is created and used in the system configuration, then the device will hang after upgrading firmware to any newer version. However, if your device’s running firmware version is not listed above, then your device is immune from this symptom.



Power cycle the device (power off the device completely, then power on the device).



1.      Please be reminded that to power cycle a device, you must have physical access to that device. You may need an on-site visit if the device is installed in a remote place.

2.      Please do backup your device configuration before upgrading firmware.


3.      Before powering off your device, it is strongly recommended to conduct the following prerequisites: Connecting the console cable. Waiting for the firmware upgrade in progress, until you see the message from the console “Restarting system”.

 Never power off your device before you seeing this message, or you might encounter unexpected result e.g. file system corruption.


(1) The console session displays “Firmware received” after the FTP file transfer is complete. Then you need to wait while the ZyWALL/USG recovers the firmware (this may take up to 4 minutes).

(2) The message here might be “ZLD-current received”. Actually, it is equivalent to “Firmware received”.

(3) The console session displays “done” when the firmware recovery is complete. Then the ZyWALL/USG automatically restarts.

Note: These patches include current hotfixes but they are not formal released firmware, it is not a “MUST” to upgrade to the hotfix versions if your device is operating normally.