I spent like 30 hours to try to install nethunter on nexus 5 but always failed. I tried to root with magisk all procedures following official instructions and succeeded, I also tried to root by flashing SuperSU-v2.82.zip, also succeeded, I also tried to use 'nexus root toolkit' to root and succeeded too. But no matter how many times I root and whatever method I try, whenever it's successfully rooted and SuperSU and BusyBox are granted and installed, I tried to flash the current offial zip file of kali nethunter (of size about 3G), it fails and then I reset to factory img. Whichever version of TWRP I try (3.6.0.9/3.2.3.1/3.0.2.0/2.8.7.2), it just keep reporting the same error msg: "failed to map file 'nethunter....img' ". I have checked SHA256 but the file is intact. And I could flash other zip files like SuperSU.zip.
What's even more annoying is that first I can't download APPs from google play store(sth wrong with the network), second I can't install a single one apk file which I transfer from PC to nexus 5 by USB cable (it constantly reports "can't open file" while any apk I download from a phone browser is installable), or even open a zip file, like there's an invisible barrier around each file that is transfered from PC. Except for the 'nexus root toolkit' method by which I don't have to install APPs, any time I have to install an APP like SuperSU, Magisk, BusyBox or TWRP Manager, I will have to search it in the browser and download the apk to install it, which is very time consuming.
I would be very much obliged if anyone can help solve a problem I met.
All the tutorials I have followed:
Official document: https://www.kali.org/docs/nethunter/
Officially recommended guide: https://forum.xda-developers.com/t/guide-unlock-root-flash-for-nexus-5x.3206930/
Installation with nexus root toolkit video: https://www.youtube.com/watch?v=L9QVULNLkug
Installation of Magisk: https://topjohnwu.github.io/Magisk/install.html