"Do not power off the device," the screen warned. If the power flickered now, his sleek five-antenna router would become an expensive paperweight. After three minutes of tension, the router rebooted with a victorious green glow.
Ensure you download the firmware specifically for the AC11 . Using firmware for a different model can "brick" the device. Tenda Ac11 Firmware Update
: Never power off or unplug the router during the upgrade process, as this can "brick" (permanently damage) the device. "Do not power off the device," the screen warned
Based on Tenda’s release notes and user forums, firmware updates for the AC11 typically address: "Do not power off the device