I had upgraded my router due to the wireless going in and out, so I'm afraid if I downgrade the firmware, those problems will return. The 4S worked fine until 6.0 and 6.01 hasn't resolved anything either.
I am currently trying to fix my router (same as op's) so that my wifi will work w/ 4s. I downloaded the older firmware 2.0.21_1.01 to my desktop from the netgear download page. However when I try to upload the file in my router upgrade tab it says the file is not compatible or something like that. The file is actually a zip folder, and in the folder it has a internet file that has the instructions for install and another file that is fragmented. I don't know where to go from here to finish changing the firmware. Any assistance?