Fails to connect to WiFi if already connected to Mobile Network

[c2oncpr]

This is a strange one. I have two HTC Vivids, same os. One connects fine to my wireless network. The other will only connect if the Mobile Network is turned off. With the Mobile Network turned on and connected, it will not connect to Wifi. It tries, displays "Obtaining ip address", but then displays "Disconnected". Anyone else having this problem. Any suggestions?

Update: Pulling the battery didn't help.

More info: As soon as I turn off Mobile Network, the wifi connects. Mobile Network can be turned back on and wifi will remain connected as long the router is in range, as it should. When leaving the router location, the phone switches to Mobile Network just fine, as it should. But will not switch back to wifi when a known router appears in range, although it tries and fails as described above.

 

[OperationA7X]

Maybe one of them got a bad update.

Sent from my HTC One unfortunately from NSA, I mean, Verizon that is now unlocked.

 

[c2oncpr]

Now that's a thought. Is there a way to revert an update and reinstall?

 

[OperationA7X]

Not to my knowledge.

Sent from my HTC One unfortunately from NSA, I mean, Verizon that is now unlocked.

 

[OperationA7X]

Unless you modify the phone, otherwise, a downgraded RUU would be rejected by the phone.

Sent from my HTC One unfortunately from NSA, I mean, Verizon that is now unlocked.