Sid you double check that you downloaded the N66U version and not the AC66U version ?
Do you have the pc attached by wire when you do the upgrade ?
Try to poer the unit off and on before you make the update of the f/w.
If you do not succeed with the upgrade you can put the unit in rescue mode
and use the mini-web gui to restore the new f/w to the router. If you have problems about setting the unit in rescue mode : press the reset button till the power led blinks slowly. You will have to assign a statip ip-address to the pc for example 192.168.1.2 with mask 255.255.255.0 if the router has a ip-address of 192.168.1.1.
Do you have the pc attached by wire when you do the upgrade ?
Try to poer the unit off and on before you make the update of the f/w.
If you do not succeed with the upgrade you can put the unit in rescue mode
and use the mini-web gui to restore the new f/w to the router. If you have problems about setting the unit in rescue mode : press the reset button till the power led blinks slowly. You will have to assign a statip ip-address to the pc for example 192.168.1.2 with mask 255.255.255.0 if the router has a ip-address of 192.168.1.1.
My wife gave me a RT N66U last week which I have been testing as an AP prior to making it my my primary router.
Was able to upload and upgrade the router to the latest ASUS version 3.0.0.4.260.
I then wanted to load the Asuswrt Merlin version 3.0.0.4.260.21.
Everytime I try I get an error message "Incorrect Version or corrupt image file." and the upgrade fails. Have downloaded the software three times from Merlins Tower and tried installing from both my PC and a USB drive connected to the router.
No problems after the failure and the router continues to work fine. In between attempts I have rebooted the router to clear memory but still a no go.
Suggestions?