We have identified some stability issues in Firmware 5.4 series and decided to remove it temporarily from our download sites for further investigation. The issues could affect Peplink devices with heavy firewall logging enabled, and may cause inaccessible web UI over a few days of use.
For Peplink devices already running on 5.4.1 to 5.4.4, you are advised to check and turn off all firewall logging options. If your device is running fine, you can stay with 5.4.x and wait for our next update. If you experience issues with 5.4.x, you can either download and install 5.3.12 or contact us for support.
For technical support, please contact us via http://www.peplink.com/contact/support/
Firmware 5.4.6 has been released to address the issues. https://forum.peplink.com/threads/1167-Firmware-5-4-6-is-Available-Now
Thanks for your support.