I noticed the post is 10 months ago, but I'm replying right now because there may be other users hunting for root solutions for this device.
How to root your Lenovo a390:
1. Download Framaroot: http://forum.xda-developers.com/show....php?t=2130276
Framaroot is an Android app created by XDA user alephzain. It allows you to root your device directly from your Android device-please click on link above to view full compatibility list. Download and Install this app. If it says "Installation blocked", go to your phone's Settings>Security and tick the "Unknown Sources" box. (Believe me, there are n00bs
2. Open Framaroot. For the a390, there is only one exploit-Boromir, since it's a Mediatek powered device. Select Boromir.
3. Now you see two buttons: Install Superuser and Install SuperSU. You need to select only one of them. Framaroot will then root your device and install Superuser/SuperSU. (Superuser/SuperSU are apps which control root operations on your device ie. ensure no app uses root features without your permission-it is a MUST.)
The choice is up to you, but I'd recommend Superuser since it's like the Industry standard of rooted Android phones.
4. Reboot your phone. You'll find Superuser installed. Open it, swipe from left to right to access Superuser settings. The su binary is outdated and it'll appear in a red font. Tap it to update su binary.
This is proof enough that your phone is rooted, but if you really need to see, here's one more step.
5. Install Root checker from Google Play Store: https://play.google.com/store/apps/d...krim.rootcheck
Run this app, and if your phone is rooted, Superuser will come up automatically asking you whether Root Checker should be granted permission- press Yes and root Checker will deliver the result.
That's it-congratulations, you've rooted your a390 without any pain. Now you can flash a recovery, install Busybox, overclock your phone, get rid of the dumb apps Lenovo has included with the a390.... Enjoy!