[Solve on S@] Similar Case for reference
Originally Posted by estebandilone
Not working... Don't know what to do
Hey dude, I had a similar case when I was upgrading my S2 officially because my USB was loose, I got the update 60% and came to a halt, my phone wasn't even rooted by then.
Here's what I did and here's what you can try:
1. root my phone (for your case, re-root your phone or even unroot then re-root it again, there may be some files damaged when your phone lost power).
2. install original kernel and Stock ROM (there might be original files which are needed from the original to make things work when you switch ROMs)
3. reboot and see if things are fine.
If you get back to running normal, then you can install whatever Custom ROMs you like.
Hope this help! Get back to me with the latest situation.