Updating unlocked att lg g3 on metro pcs network.

Ive seen some videos about updating to lollipop stock rooted rom but I'm not sure if I'm able to do this without messing up the phone. I bought the phone unlocked and rooted so I'm not sure what was done to it but I really just want to update to the latest stock rom without losing everything on my phone if possible.. sorry I'm really knew to this but i do have all the programs to do the installs just not sure if I can do this like I said. Any help advice or direction would be appreciated!

Unlocked 900A from At&t to metro pcs / T-mobile successful But can I root/rom it?

Hello if anyone could point me in the right direction, it would be appreciated.
Basically I unlocked an At&t s5 900a to Metro pcs yesterday, everything seems like it's working but the phone is still on the 4.4.4 stock At&t rom, can I root / put a different rom on it being that it's originally from the At&t network / phone? If so, would I need to put a metro pcs rom on it or at&t rom? I really just want to de-bloat the at&t apps and have it rooted so i can tether it. Anyone have any insight on this?

Flash Tmobile H631 Rom into Metro PCS LG G stylo MS631 device

I have a Metro PCS LG G stylo that's rooted and unlocked, running on the T-mobile 30 dollar plan. I want to be able to use WiFi calling among other apps from Tmobile. Can I use TWRP to flash the Tmobile rom into the phone?

Flash Tmobile H631 Rom into Metro PCS LG G stylo MS631 device

I have a Metro PCS LG G stylo that's rooted and unlocked, running on the T-mobile 30 dollar plan. I want to be able to use WiFi calling among other apps from Tmobile. Can I use TWRP to flash the Tmobile rom into the phone?

Is there a low volume Fix for Metro pcs ver of stylo

I would like to know if it is possible to boost up the over all volume on headphones listening to apps like tune in radio and netflix the volume has to be cranked up all the way , also would like to know if the speaker volume can be tweaked or is it not worth it? I havent tried a volume booster yet that has made any difference but for anyone that is a music nut i have noticed that Power amp can be tweaked up gain and eq settings sounds great really puts ipods to shame!