Asus RT-AC88U rapid flashing power LED light after firmware upgrade

I have an Asus router that is flashing rapid lights on the power LED indicator. It won't factory reset or boot into recovery.

It started doing this after the official firmware update. It did this a month ago after last official firmware update, and after messing with it for hours, reading several threads, and trouble shooting it finally just started working.

I can't access the GUI or any router settings. Nothing will broadcast Ethernet or WiFi.

I called Asus tech support and they want...

Asus RT-AC88U rapid flashing power LED light after firmware upgrade