Almaretto wrote

When I had 5 Ghz network hidden, I would have trouble connecting as well as relatively frequent disconnects. Since I un-hid, my connections have been stable. I have mine on AC/n as my cell phone is the only AC device I own.
For 2.4Ghz, I had trouble with some peripherals like NAS hard drives and printers until I switched it to mixed mode.
I am using DHCP reservations, but no bindings.

That is why I asked. Seems there are obviously some bugs to work out in beta.

No I never need to hide SSID's, but I do have an update.

On trying the beta code again I realized my PC had two DHCP entries with different addresses as a consequence of loading the bindings (no spaces or non-alpha numerics, mind).
I thought this should be no problem, but nevertheless rebooted PC and router (again).
Oddly the original problem of no association at 5G seems to have gone.
Can't really explain it other than poor scientific method; maybe rebooting everything again was the key, but I don't see what DHCP has to do with basic association....

I installed "Archer_C9_V1_150908_beta" firmware on my C9 v1 today. When the device tries to assign IP addresses according to my DHCP reservation list, the DHCP system completely fails and no device can get an address assignment. Thus, this problem is NOT SOLVED in the new beta firmware. I guess I'll go back to the May, 2015 firmware for the time being.

freemansteve wrote

No I never need to hide SSID's, but I do have an update.

I only hid temporarily while I setup the router via wireless.