Firmware 7.6.3 kills 5 GHz channel in Airport Express

Yes, same here. Airport Express 802.11n's can no longer see 5GHz network with new firmware.

Well I gave it all a try. Upgraded the three 5th gens, then rolled them back and upgraded again. They seemed to work for about 15 minutes then things started to go unstable. The primary started giving errors about double NA'T and handing out DHCP and the cable modem was rebooting like crazy. When it was working the speed test app is all over the place to, never stable and some times it hangs and if it does that you have to toggle wifi on and off to get Internet to come back on that device. All three routers act the same. Tested with MacBook Air, iPad mini, IPhone 5 and Latiude e6220 with 6300 intel wifi chip. I rolled the all back for now to 7.6.1 and Cable is now stable, routers are all stable, no more hangs and weird stuff. My speeds area ll back to normal and my shared drives and wifi printer are back as well.

This is correct. The firmware upgrade will break an Airport Netwrok connectiong other Airport Express modules. It cannot see them any longer. However, I do not know how to roll back the firmware upgrade. Any info on how to do that?

Yes. Download AirPort Utility 5.6 if you don't have it. Open and select the AirPort device that you want to rollback firmware to 7.6.1. (it will be all in your network.) Click on Base Station on main menu bar, then select Upload Firmware, select 7.6.1 from the menu, click OK and you will be back at 7.6.1 shortly.

However, I do not know how to roll back the firmware upgrade.

Open AirPort Utility 6.2 and click on an AirPort Express

Hold down the option key on your Mac while you click on the version number of firmware. A drop down of available previous versions for the device will appear. Click to select the version that you want.

When I do this, I do not get a drop down. I have a horizontal arrow instead of a vertical one.

When I do this (upgrade firmware from the drop dwn menu) , it asks for a file from my computer. Is the 7.6.1 file still located on my computer somewhere?

Well, I've rolled back all my AirPorts to 7.6.1 or 7.6.2 and the AirPort Expresses still cannot see the 5GHz network to extend it. And it all worked before updating to 7.6.3.

Make sure the upgrade didn't remove your 5g name or the 5g settings in the AirPort Extreme. It did this on one of my Extremes some how and I had to add that info back in. It also changed the auto time check to off on one and enable setup over Wan on another. Good luck.

The firmware is not on my computer anymore. The new update deleted it. Also, Apple deleted all the airport firmware downloads from the support web site. I'm not a conspiracy kid of guy, but this is really wierd.

Google airport 7.6.1 airport firmware down load and I bet you can find a copy. Good luck

Sorry, but I cannot duplicate the error that you are reporting.

I have toggled back and forth 3 times downgrading and upgrading various versions as a test and everything goes very smoothly.

If I can manage to break it, then maybe I can figure out how to fix it. So far, no luck.

My bad. The AirPort Expresses now see the 5GHz network and can extend it when rolled back to 7.6.1. I was too impatient.