Administration - Firmware Upgrade
  1. Previous firmware versions do not need to be installed prior to installing the latest firmware. The latest firmware version will include updates from earlier firmware.
  2. For a configuration parameter existing both in the old and new firmware, its setting will be kept during the upgrade process.
  3. In case the upgrade process fails, RT-AC66U enters the emergency mode automatically. The LED signals at the front of RT-AC66U will indicate such situation. Use the Firmware Restoration utility on the CD to do system recovery.

Please visit the ASUS support site ( ) to get the latest firmware.
Product ID RT-AC66U
Firmware Version
New Firmware File