I was so happy to upgrade the router, but seems my RT-AC68U is bricked with this upgrade!
I did the update as usual and went fine but after i did the factory default the router goes on loop every minute and doesn't start anymore! i just got the power led on, all other light are off, WIFI doesn't start, so i try to connect with cable but i'm not able to access the admin page, seems the firmware is not able to start. I try also a hard reset with the button, no way! I'm really upset I hope there is a solution.
My router before the upgrade,
FW 376.49_4
bootloader 1.0.2.0 eu (upgraded from 1.0.1.6)
CPU 1000mhz
Why the factory default made my router dead??
Did you have the turbo mode enabled before the upgrade? I had enabled that on my 68U and ran into the same symptom. After I hit the button to disable that it booted without issue and I then found the admin page said my router was no longer compatible with turbo mode (due to the updated booter).