[Galaxy S II Q&A, Help & Troubleshooting] shaunak:
What I did:

1. Formatted (Wiped) the entire phone, Internal SD card included. (Just take a backup of your files on your pc, you can use an app, I chose to copy-paste everything on to my laptop.)

2. Downloaded and flashed the stock Samsung ICS rom from here using Odin. Just follow the instructions, it's pretty simple.

3. Rooted my phone using the instructions here.

4. Downloaded CM9 from get.cm and flashed that and a signed copy of GApps I had using CWM.

NOTE: You will lose all the data you haven't backed up, yes including photos, videos and everything else that's stored on your internal SD card.

1. SMS Messages & Call Logs: In my case I'd synced my contacts with gmail so they got re-downloaded. I chose not to backup anything else so everything's gone. You can use these apps to backup your sms messages and call logs.

2. Preferences / Settings: You'll have to re-do it all.

3. Apps: Even though the convenience of the 'App+Data Restore' is very tempting, don't. Just don't restore your apps using Titanium Backup. Re-install all of them from the market. Yes, it takes a while but it's worth the trouble.

Essentially what I got after my experiment was a brand new - old phone. I re-installed only what I needed and restored only those files which I wanted on my phone. Everything else is on my laptop. It took around half a day to download, flash and install everything but like I said it worked like a charm.

I'm updating my old post here in case someone is facing similar problems. Hope it helps! :)

ORIGINAL POST BELOW

Problem: Push Delay

Mostly it's my Whatsapp messages which are delayed. A 15-20min delay I'm fine with but here they're getting delayed by hours, sometimes as much as 6 hours. It also happens with Instagram notifications, which sometimes just don't appear.

Solution: Ended up being a network issue. In case of Vodafone India, get in touch with them on twitter [@VodafoneIN], it's the best way to get a quick response. They sent some executives to my house and got the signal strength tested, not sure what they did after but now there's a significant difference in my network.

Problem: No Twitter Notifications

Whatever client I use for twitter, I just don't get any notifications. I've currently switched to the official app and selected the needed options in both Accounts & Sync and the twitter app. Still no notifications - when I open the app it shows that I have new mentions but it doesn't push them to the notification bar.

Solution: Again, not sure why but whenever I have Show Notification Count checked the twitter notifications don't show up. Unchecked it and it's working fine. (Settings > System > Status Bar > Show Notification Count)

Problem: Freezing & Battery

This happens randomly, mostly when I click on an option in an app (Eg: click on the camera in instagram.) The phone freezes for a few seconds and shuts down. All this happens within 1 minute and the phone instantly heats up, not the normal heating but a lot more. When I restart the phone, no matter how much battery there was earlier, it shows less than 5% and the phone shuts off again. Sometimes I wait for around 10 minutes and restart it again and the battery level is back up (around 10% less than before) and the Battery Usage in Settings shows a gap.

Solution: Got a new battery. Every battery related issue is now solved.

Problem: Data Services Hang

If I wake the phone after a few hours on standby, the data service hangs up. It shows the 'H' or '3G' in the notification bar but it's not active. I have to go to settings and disable / enable for it to start working.

Solution: Flashed a new modem, tried a couple till the problem stopped. Thanks a lot for the screenshot, theunderling.

Problem: Battery Drains

The battery level is inconsistent. When the phone is in standby for a few hours, the battery drains more than it shows. Sometimes it shows as 20% - 30% but drains within half an hour.

Solution: Again, the new battery.

Problem: Network Drop

Since updating to 9.0.0 this happens rarely but the network drops completely for a minute and then comes back on. It started with RC2 and happend every time I tried to place a call but now it happens randomly, usually a little before the phone freezes.

Solution: Get a new modem. Look up the screenshot in theunderling's post below, that's where you want to start.

I used CWM to flash the ROM and before I did, I formatted the system, data & cache and wiped the Dalvik Cache & battery stats. I was told earlier that the problem was with my Kernel and I downloaded and flashed another one from here but that didn't make any difference. Please help me out! My phone is becoming impossible to use now! :(

Battery Screenshot

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