3 RT-AC5300's upgraded(384.45149) quickly downgraded(384.32799)

[Jim Kirk]

See signature for my RT-AC5300 configuration.

This reference thread also describes RT-AC5300 upgrade issues:
https://www.snbforums.com/threads/asus-rt-ac5300-firmware-version-3-0-0-4-384-45149.50244/

I have about 25 wired clients and 15 wireless. Before the upgrade, I was set up with a 2.4GHz and two 5GHz bands set up as Smart Connect.

• I upgraded on a W10 x64 PC using the router Web UI. No problems all 3 upgraded fine and I could see all both nodes and Parent had 45189. I had 3 separate bands as described in the reference thread. Two usable and 1 inaccessible.
• I then checked iPhone XS max speedtest app while close to each node. Both getting 400-500 Mbps DN and >300 Mbps UP. Looking good at nodes.
  
• Then, I checked speedtest at Parent. OMG. 20-50 Mbps UP and about same DN. Sometimes worse. Really bad. Before 45189 I tested as good with my speeds as I was getting at each node.

After the upgrade I had the a 2.4 band, a usable 5 band and a no longer accessible 5 band. Exactly as described in the thread I referenced.

So, besides having one of the 5G bands taken from me by the 45149 FW my Parent was hopelessly slow.

I figured here goes my day and I decided to restore everything back to 32799. Not so, took only about 1/2 hr working from Web GUI with complete success.

1. I first loaded FW 32799 for the two nodes from the Web UI Administration>FW. Each node rebooted automatically and after each reboot, I refreshed the Parent Web UI interface and it showed 32799.
2. I then loaded 32799 for the Parent. I rebooted the parent manually and I could access the Web UI. 32799 was on Parent and both nodes.
3. I had 3 bands with one of the 5G having "_dwb" still at the end of the SID. 5G Smart connect was not on in Wireless>General so I set in back on with a single SID.
4. Amazingly, all worked well and speeds now all back to normal.

As LIMJK asked in the reference thread and I strongly second this:

"Asus, please give me back my Tri-band - Thank You!"