Forcing higher USB current
This is to point out a possibility of replacing echo option, with a copy paste option

( Before that, here is a similar search Prevent complete charging?. .)

Related efforts  and success for AC charging by replacing the file itself, when echo was not possible, (for reasons I still don't know) is my answer for Honor 6 phone here How do I override charging current on Huawei Honor 6?. 

On a side note, similar effort for Samsung Note 2 https://android.stackexchange.com/questions/127288/over-ride-charging-current-on-note-2-n-7100 has not yielded a solution. Unconfirmed views are :


Kernel alone can do that for this phone (from two kernel chefs who made kernels for this phone)
Chipset limitations. This from a developer


Since their views are based on email, cannot quote names

All the best and will be looking to find if there is yet another way