Look no further I have your solution!
First off you need to go on your computer and Google "official Samsung galaxy s 2.3.6 update xxjvw4" you should find a blog/website with a download link to both the update and a program Odin. There will also be an option to go to the next page on rooting the update. Download the CF Root file. Now your ready to go.
First off backup. Secondly go into download mode on your phone (shutdown then turn on holding down+power + home.) Then a screen with a hazzard sign saying downloading will appear. Now plug in your phone to your pc
Then open Odin. You will then need to select your files... First off click the PDA Button and locate the update folder (forgot to mention that it must be extracted) after selecting the file click the Run button on Odin. This will install the official sgs 2.3.6 update. Once done you need to root. Go back to odin and click pda again. Now select cf root and then ckick start again.
You are now rooted!!!!
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