I have a WRT1900AC v2 that had a bad DD-WRT flash and wouldn't boot. I assembled the serial port connection and connected however, nothing comes across the serial console. I'm using a USB to TTL Serial cable. Only using GND, RX, and TX. Upon power on with the cable attached the esata light is lit and nothing seems to happen. Has anyone encountered this? Solutions?
Just a wild guess: Maybe the USB2TTL draws to much power and this will stop the router from booting (i think i read something like this a time ago).
Wait 2-3 seconds after powering on and then connect RX. Do you now get some messages?