Wi-fi problem with LG P405g since upgrade

[SChamp]

Hi

Since I've upgraded my phone to V20A and Android 4.1.2 my cellphone's wi-fi keep losing the connection with my router after it goes on standby for about 15 minutes.

I tried to do a hard reset, reinitialize to factory values and event restarting my router. Is there any way to downgrade my phone?

Thanks

***Edited to add labels***

[FidoStephane]

Can anyone on the forum help out with this?