Downgrade to A6, then you can get OTG on stock romI flashed TWRP 3.1.1-1 and EKR 7.3 that you provided and still have not got OTG working (using EliteROM v7.7).
I also tried command in the post above which only seems to disable charging and power some of my devices (like usb headphones which starts glowing but without sound or headphone in notification bar), some devices do not even receive power (my usb keyboard) and usb flash drives are not present in File Manager (do i need to mount them manually? - if they even get power considering they have not got led indicator).
Also i am now using EliteROM v7.7 for five days and sometimes Camera Flash turns on and can be only turned off only by restart.
I will surely return to stock rom soon and try other otg solutions, or just buy a new phone. This rom is maybe faster but definitely not stable like stock rom.
Thanks for your time