A small correction and advice for my previous #2
Samsung Kies and Odin operates separately and should not be mixed as they can interfere with each other. They both provide the drivers etc. to close the USB link between your PC and the Galaxy S II. Kies should only be used for Samsung officially approved upgrades.
My unofficial upgrade to v. 4.0.3 is working great,the only apps not compatible are the Big Buttons (BB) keyboard and the Music
Hub which comes installed. This will no doubt be corrected in the future.
BUT, ´Curiosity killed the Cat´, feeling full of confidence after my upgrade,I repeated the exercise when I was told v. 4.0.4 (also unofficial) was available. This time I managed to crash my Galaxy S II,unable to revert back to v. 4.0.3.
Mistakenly I thought the Kie software
also had to be present and it continuously refused to set up the USB bridge. After many internet
consultations I deleted Kie and uploaded v. 4.0.3 instead,which I luckily had saved. This time all went famously and I am happily back with v 4.0.3.
Just thought you like to know,avoiding the same mistakes