A few weeks ago, I upgraded my brand new Galaxy S from the original 2.2.1 to 2.3.2 beta. Assumingly, this caused disappearance of the mobile AP function. Since it is crucially important to me, I'd like to go back to the original firmware. Clear, I can't do it with Kies. Is there any other reliable way to do it ? Are there step-by-step instructions ? Thanks.