there is some chinese root applications : kingoroot,vroot ( seems kingoroot "steal" method from vroot or vise versa )
anyway, this stuff, beside root, install few applications and kinda download something from somewhere.
i'm extracted their root method,cleaned it from encryption and repackaged it as standalone application, which is definitely not install any stuff, except su and busybox
i don't know on which phones and firmwares it works, but it is definitely work on latest 4.x firmwares, i'm tested with xperia t,tx,e,tipo,s, etc.
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