[G4 General] ling751am:
Before asking any question, be sure you have already checked this Q&A list!

Known Issues:

Q1. I'm stuck at LG Logo after flash 5.1 KDZ

A: Pull out battery and enter recovery mode to do factory reset

Q2. Will my G4 overheat or dead while flashing?

A: All G4 still alive now won't dead, while flashing, they mutation

Q3. Should I upgrade to Nougat? Is there any feature better than Marshmallow?

A: Google "Nougat vs Marshmallow"

Q4. I'm now at 6.0 and Anti-rollback version is 0, do I need to downgrade before flashing Nougat?

A: Go to the top and read this topic again, GO :(

You can't unlock bootloader that mean you can't dump out system.img to do root injection

And you can't use TWRP cuz you have a locked-bootloader

So, we need to downgrade, using the 5.1 Download mode to flash our modified system.img

Gain the root permission and use FlashFire to flash that firmware

This method looks like HTC's Bootloader firmware flash, but we use FlashFire to do this :)

Q5. Will Nougat cause G4 overheat or battery drain?

A: No, but smooth and stable, surfing web just a little warm

But I don't play games, so you need to try this urself

Q6. Hey! Is there any root injection in this Nougat firmware?

A: No, this is an official firmware signed by LG, un-touched, so ... sad :(

Q7. Can I do a root injection to this nougat system.img?

A: No, you can't, go back to Q4

If you modified the system.img and flash it

You'll get a fully bricked phone

Q8. Why I should do factory reset again after nougat boot up?

A: FlashFire flash that firmware just like when you receive an OTA and flash it

That a dirty flash, will cause lag, overheat, or other issues.

Q9. Can LG Backup restore all my data?

A: Some applications can't backup their own data,

but I know Steam Guard can!

Cuz I just logged in my Steam through that restored Steam app!

Q10. Can I roll back to Marshmallow or lower version?

A: Yes, you can!

But wait, check Anti-rollback version, if the value is 0,

then use LGUP, "REFURBISH" your phone to European v10 KDZ

Check anti-rollback version still "0"

After flashed European v10 KDZ, REFURBISH your phone again to any country/version's KDZ

Q11. Hey! Why my rootsystem20160214 not a img file, it's a 7z format file!

A: Don't you know that a zipped format? Go search it.

Q12. OMG! My phone stucked at LG Logo with breathing light

A: It's still boooooting, don't take out battery or anything else, let it boot up.

Q13. My phone realllly stucked at LG Logo, and LGUP show Unknown Model or Unknown Port!

A: Try LG Flash Tool, flash TWN v10F KDZ or other country KDZ.

If your LGUP or LG Flash Tool can't recognize your G4, and you surely the driver correctly installed...

The reason is: Windows 10 with USB3.0 port won't work, try Windows 10 with USB2.0.

Quickest way: Why not use Windows 7?

Q14. Can I get Android Pay working if I upgraded to Nougat?

A: You can't. Some "root" files still in the system partition (I don't know where are those files stored).

So your phone can't access SafetyNet now.

Q15. Is there any way to get my Android Pay work again?

A: Try REFURBISH your phone to a European KDZ

Then REFURBISH to any country/version KDZ, that's would get your Android Pay work again.

Oh.. I didn't try this but I think it would work, cuz I don't use Android Pay :)

Q16. So, why can't we access SafetyNet?

A: Some "root files" can't removed from the system partitions, if Google Play services detected those files, may cause "CTS Profile match: Fail"

Q17. Everything worked fine after this upgrade, but it shows "Current Version is not available for user. Can't find cust for NTCODE=[XXXXX,FF}", how to solve this?

A: It's normal cuz the firmware doesn't match to your phone's region / country, dismiss that, and enjoy your nougat :P

Q18. I can't get 4G+ on my G4, why?

A: This firmware's baseband doesn't match to your country's band, not a major issue.

If you really care about this, downgrade to Marshmallow

Screenshots:

See attach