I have found a work around for the battery drain issues after the 2.3.6 update to my GS2. I consider this to be a work-around, because an actual fix would involve someone at Google or Samsung actually correcting the buggy code. I am dividing this up into several sections that describe the work around and the rationale behind it. I'll start with the fix and save the details for later. ************ The Problem After the 2.3.6 update I noticed a sharp decrease in battery life. I went from being at more than 70% battery at the end of the day at work to being at 50% or less. I tend to keep WiFi on all the time because I connect to the network at my house, the AT&T store that is next to the place where I stop for a bagel in the morning, and at the office. I noticed that instead of "Display" being the biggest battery hog (as I was used to), it was now "Android OS". I was quite concerned because I was about to go on a business trip, and would need my phone for checking email, returning phone calls, etc. While on the trip I kept WiFi off, and I noticed a significant improvement in battery life, even though I was checking email regularly via the 4G connection. That was the first piece of evidence that the root cause f the problem was related to WiFi. ************ The Work Around The following worked for me, and I think will work for others. 1. Go to Settings -> Wireless and Network -> Wi-Fi Settings. Tap the menu key and then Advanced -> Wi-Fi Sleep Policy. Select Never. (This is counter intuitive, but I will explain the reason for this below.) 2. Download a 3rd party battery manager that can control WiFi. I am using Battery Defender, which is free. Juice Defender Plus and Ultimate should also work. (I don't think that the free version of Juice Defender controls WiFi.) If the market tells you that Juice Defender is not compatible with your device, I think it is because AT&T doesn't want you to use it. You can probably side load it, or pop out your SIM card and download it over a WiFi connection. 3. Set up the battery manager of your choice to control your WiFi connection by turning it off when the screen is off. Battery Defender is a bit of a blunt instrument in the sense that when your screen is off, WiFi is off. Juice Defender is a little more sophisticated because it turns WiFi on periodically (every 15 minutes) and allows background applications to connect briefly. If you rely on push e-mail and/or social network updates, you will probably prefer Juice Defender. 4. Enjoy improved battery life where your Display now is the biggest consumer of power. ************* Why This Works Based on reading a number of posts in this forum and others, there is good evidence that there is a bug in the operating system's Suspend process. Normally you would let the operating system manage the WiFi connection, and it can be set up to turn the WiFi off when the screen is off (that is one of the options in the WiFi Sleep policy settings). What appears to be happening is that the Suspend process has a bug and when it shuts off the WiFi radio it goes into an infinite loop of some sort that burns processor cycles and uses a lot of power. This shows up on the battery usage screen as "Android OS". By telling the operating system to never put the WiFi to sleep, the buggy Suspend process never runs. By itself, this would involve a trade-off between the power consumed by the WiFi radio and the buggy suspend (I actually think that leaving WiFi on all the time would use less power). By installing the 3rd party battery manager you are having another program sneak in and turn the WiFi off at the hardware level. The operating system is not involved, and the Suspend process does not start. ************** I hope this help those of you who are having problems. Al