ASUS ZenFone 2 System.img <== Z551ML HELP! (Root)

[wpan2002]

Well i went here since the xda forums didnt respond to me and LinusTechTips Forum Community never fails me 

 

http://forum.xda-developers.com/zenfone2/help/how-to-upgrade-cn-version-to-ww-t3101556

 

Now i got a ASUS Zenfone 2 got it for free since the seller was sending the wrong one and also he sended me a CN Model so i flashed it with the WW Firmware and seems to work now i see my firmware was outdated alot so i set off trying to update it

Not Sure if LTE will work since i am planning to get it but i am just chilling at prepaid 

 

Specs:

Intel Atom 1.8GHz

32GB Internal Storage

4GB RAM

1080p Display

 

Now i unlocked the bootloader and install twrp soo i am wondering what to do?

I fastboot it before with a system.img i downloaded but now everything i download is not working i did all the stuff in linux it keep giving me errors for the 2.20.40.90 <=== Latest version when i try to do fancy stuff to it to make it rooted but never work out

 

when i downloaded the file from the mega link the zip shows up in linux but when i click it it give me a error and that is the zip file containing the System.img so i am going crazy i was trying for 17 Hours of my day just trying to do it and i havnt have a meal for the whole day just because of trying no breakfast, lunch, dinner soo i am not sure why is it soo hard XDA Forums dosnt seem to respond to any of my post so i hope you can  

 

Also if you have a tip that requires a unlocked bootloader i already do and also with a Custom Recovery TWRP 

Also i am not going to install CM since it is not offical or any unoffical roms since i dont want to deal with the issues and i am just fine with the normal one just need to remove the bloatware and also some root stuff i use like Titanium Backup, AdBlock, Cheating stuff and there is much more uses that i need to complete my android experience so if anyone have this device and willing to help me make it or tell me a really working way it will be nice

 

I cant do OTA update since

1. Original was CN

2. TWRP

3. Root Method PreRooted System.img