I am a new member here and I have maybe an solution for all you out there who keep tryin to root the ICS 4.1.B.0.431 version on their Xperia Arc
It worked for me so please feedback and correct me if i am wrong
So I done that like this:
1. I downloaded the stock ICS 4.1.B.0.431 for my Arc.
2. I flashed it on my Arc with flashtool.
3. Then I tried to root it with Rooting Toolkit for Xperia 2011 ICS by Doomlord ( ) but no succes
4. I found that thread: [07/04][arc/arc s][ics 4.0.3] very stabe, smooth, nice and best for battery fc3.0
5. And in this thread I found that kernel:
6. I flashed it on my Arc with the stock ICS
7. I used again the Rooting toolkit by Doomlord
8. And voiiiiiila........i got root!
As mentioned I tried that and it worked for me