After successfully unlocking my bootloader and rooting my Axon 7, I started installing tweaks and mods to see what would work normally and what needed extra work to get working. AdAway is the only tweak I have found so far that did not install as smoothly as it normally would on some other devices, usually you just get the app and give SU permissions, then press the "download files and apply ad blocking" button and thats all, applying the modifications to the hosts file and one reboot to finish, but no matter target path I used (even though the hosts file is in fact located in /system/etc/hosts on the axon 7), I would keep getting an error with copying files to hosts. Now, I may have missed something incredibly obvious and possibly could have come up with a much simpler way of installing AdAway, but I am simply sharing my experiences.
Here is what I did to get it working on my A2017U running B29 stock rooted:
-Installed latest AdAway apk from XDA (link below)
-Downloaded the AdAway_systemless_hosts_v2.zip and flashed via TWRP recovery
-Reboot then go into the AdAway app and press the "Download files and apply Ad Blocking" button, it should complete quite fast
-Final reboot and you should be all set with AdAway installed.
All credit goes to the AdAway developers and mrRobinson at XDA for all these awesome tools and files. Of course we all know ads are needed for developers to make money in order to provide us all with awesome free content, so it is most helpful to use this tool to test your own apps or to bypass any ads that may be prohibiting the proper use of someone else's app. Below I have the XDA link to the AdAway apk, and the link to AFH for the systemless_hosts zip file (credit goes to mrRobinson)