I have been trying too Root my S291 for a whole day yesterday. I followed this manual by jozco313:http://forum.xda-developers.com/show....php?t=2762565
I tried doing it on two different computers and I had the same problem in both. After I install the drivers on the computer and enabling USB Debugging I open the Root tool and click on the first option, after that my phone shut off (maybe it's still on but with blank screen I'm saying that cause after I click the first button on the Root tool I hear USB disconnect sound and after a second+- I hear the USB connect sound meaning maybe the phone did reboot itself like it supposed to but nothing is happening on the computer or on the phone).
What can I do?
Btw the phone came with a multilanguage Stock ROM B04, today I managed to update the ROM to B11 and tried the root again but I had the exact same problem.