[Android Q&A, Help & Troubleshooting] Vulturon:
Mr. Migo, thank you for replying. But I have more to ask/... Sorry for being annoying, because I am a beginner and I wish to make things clear, to minimize the chance of accident...

1. you said i'm good to go now, but shall i need to .kdz flash the stock v21a-HKG-xx which is Android 5.0 first? because i remeber RR rom's post in xda said i should upgrade to 5.0 first... i'm not quite sure...

https://xdaforums.com/lg-g3/development/rom-t3507493

above is the link of the rom, I wish to know is my phone appropriate for doing this before everything... Hope Mr. migo you can have a look for me when you have time...

2. regarding twrp recovery, i read this: https://xdaforums.com/lg-g3/development/recovery-twrp-3-0-0-0-t3309475?nocache=1 however in the official download link it said twrp for d855 europe... I'm D855 but not europe... If I want to flash official latest twrp recovery, shall i use 'twrp manager' from google play?

plus, it said i should backup the original stock recovery, how do i do that?

3. Doing a full nandroid backup which can be used to completely restore current status, only including 'system, data, boot, efs', the 4 partition, correct? because i didn't use any custom recovery before, so i wish to know more... any other things need to pay attention before doing a full nandroid backup?

4. I wonder which version of Gapps I should flash / appropriate for the RR remix... the post said Download Gapps (ARM 7.1 Pico/Nano/Other), but which I should use? 'cuz it is essential I think...

5. Hope you can check my understanding below: if i want to flash RR rom now, should:

--- flash official latest twrp recovery

--- go to recovery mode (twrp) & backup 'system, data, boot, efs', the 4 partition in ext.sd card

--- still in twrp recovery, do 4 wipes 'system, data, cache, dalvik cache' (I want a very clean installation, not 1 byte of previous rom data will be left, so how can i wipe it to very clean status?)

--- after 4 or 5 wipes, do i need to press 'factory reset', 'wipe cache partition' these 2 options?

--- alright after all the cleaning, still in recovery while the device is like a shell (nothing, no OS inside), browse to ext.sd card which I will be putting the .zip ROM file, and flash it.

--- after completing flashing, do i need to press 'factory reset', 'wipe cache partition' these 2 options?

--- then I shall flash gapps?

--- then, reboot device, and I am done?

6. I want to know is this ROM really appropriate for my phone... because all those screenshots are in foreign language, not even English, I live in Hong Kong and I bought this phone in Hong Kong... So will the RR remix rom not compatible with certain regions...

7. Again this link: https://xdaforums.com/lg-g3/development/rom-t3507493 below 'Download on AndroidFileHost (AFH)', there are several version built in diff. dates. It seems that the latest build is Nougat android 7.0...? Willing to try that, but is it better for me to go to Resurection remix official site and search for d855, then download the latest, stable (not Nightly) builds?

8. This is how i change DPI. I calculate using dpi calculator, 1440x2560, 5.5inch device should have 534.06... dpi, then i use nomone resolutrion changer to view the default settings (1440x2560, 5.5inch = 640 dpi), then 640 / 534.06 = 1.19836...

then, dpi calculator agaim -> 720x1280, 5.5inch device should have 267.6532... dpi, then 267.6532 times 1.19836 = 320, I will do this in terminal with command 'wm size 720x1280', then 'wm density 320'. and go to build.prop, find "ro.lcd.sf.density' change value to 320, then reboot.

Is my method correct? I think it is not too low... Approproate value for 720x1280 res. monitor.

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That's all for now, sorry for so many questions... really... I just wish to minimize and get everything clear before proceeding, since this can be dangerous... thanks a ton Mr. Migo.