Astrill Setup Manual:Getting started with ASUS Merlin firmware for routers - Astrill Wiki
ASUS RT-AC66U Router Review: AiMesh System Setup
Asus RT-AC66U - Installing the ipkg Command : FATMIN
Amazon.com: ASUS AC1750 WiFi Router (RT-AC66U B1) - Dual Band Gigabit Wireless Internet Router, ASUSWRT, Gaming & Streaming, AiMesh Compatible, Included Lifetime Internet Security, Adaptive QoS, Parental Control : Electronics
My Asus RT-AC66U with Merlin was hacked and I only found out because of Pi-hole : r/pihole
How-To Install Asus Merlin Firmware with AiMesh : Cheap Mesh Network - YouTube