Consider adding warning when attempting to disable both bands

[jaredbrogan]

I just experienced the same issue as described in this reddit post: https://old.reddit.com/r/tmobileisp/comments/1ejuz98/g4_gateway_stuck_powering_on/

When using the gateway (at least the G4SE model) without its router enabled whatsoever and utilizing a separate router, this results in the gateway being stuck on a "Powering up" screen after the next reboot. Being that this is only affecting the wifi capability of the gateway, the wired connection to my separate router still works just fine. When this is encountered, a factory reset is required to fix the issue. Once reset and reconfigured, you can then hide the gateway's SSID in the T-Mobile/T Life app and then only disable the 2.4GHz band in HINT. Apparently the 5GHz band is required to stay on, otherwise the "Powering up" issue happens.

I'm not sure if this was caused by a recent firmware update (currently on version 1.03.14) as I'm a new user of TMHI, but seems like it's a possibility at least.

For added context when the issue is happening -- HINT's Wi-Fi section fails to load giving the following response body:

{
  "result": {
    "error": "SetFailed",
    "message": "WiFi driver is busy. Please try again later.",
    "statusCode": 408
  }
}

[zacharee]

This is a bug in the firmware and it seems to be happening on every unified API model (KVD21 and later). I think I might make it so it's impossible to turn off the 5GHz band for unified API gateways and show an informational dialog.

[jaredbrogan]

Yeah, probably for the best given the impact.

[zacharee]

1.13.2 makes it impossible to turn off 5GHz WiFi (much to the chagrin of Play Store reviewers apparently), with a message explaining why.