How to downgrade from Marshmallow 6.0 to Lollipop 5.1.1?

[AC Question]

I updated my system a week ago from Lollipop 5.1.1, I have an LG G Stylo from Metropcs and I noticed after updating, my phone been lagging and slow, my apps have been closing even after force closing them, the battery have been draining it doesn't even last a half a day. I want to know if Its possible to downgrade from Marshmallow? Please and thank you.

 

[tube517]

Have you cleared your cache partition?

 

[Rukbat]

It's not possible, it's only possible to install the full 5.1.1 - if you can find a 5.1.1 ROM for that particular model phone and if you download the LG flashing tool (there are two, and there are two ROM formats - match the tool with the format of ROM you find).