*#*#4636#*#* Display information about Phone, Battery and Usage statistics

*#*#7780#*#* Restting your phone to factory state-Only deletes application data and applications

*2767*3855# It’s a complete wiping of your mobile also it reinstalls the phones firmware

*#*#34971539#*#* Shows completes information about the camera

*#*#7594#*#* Changing the power button behavior-Enables direct poweroff once the code enabled

*#*#273283*255*663282*#*#* For a quick backup to all your media files

*#*#197328640#*#* Enabling test mode for service activity

*#*#232339#*#* OR *#*#526#*#* OR *#*#528#*#* Wireless Lan Tests

*#*#232338#*#* Displays Wi-Fi Mac-address

*#*#1472365#*#* For a quick GPS test

*#*#1575#*#* A Different type GPS test

*#*#0283#*#* Packet Loopback test

*#*#0*#*#* LCD display test

*#*#0673#*#* OR *#*#0289#*#* Audio test

*#*#0842#*#* Vibration and Backlight test

*#*#2663#*#* Displays touch-screen version

*#*#2664#*#* Touch-Screen test

*#*#0588#*#* Proximity sensor test

*#*#3264#*#* Ram version

*#*#232331#*#* Bluetooth test

*#*#7262626#*#* Field test

*#*#232337#*# Displays bluetooth device address

*#*#8255#*#* For Google Talk service monitoring

*#*#4986*2650468#*#* PDA, Phone, Hardware, RF Call Date firmware info

*#*#1234#*#* PDA and Phone firmware info

*#*#1111#*#* FTA Software version

*#*#2222#*#* FTA Hardware verion

*#*#44336#*#* Displays Build time and change list number

*#06# Displsys IMEI number

*#*#8351#*#* Enables voice dialing logging mode

*#*#8350#*#* Disables voice dialing logging mode

(all credits to Renjith)

AndroidUsersGuide-40-en

For user, who have difficulties running ADB on Windows PC here’s the step by step instruction (tested myself, working on W7 Ultimate) :

ADB for Dummies

Note : I AM NOT TAKING CREDIT OR DONATIONS , OR ANY OTHER BIT OF THE GREAT PRO BONO WORK DONE ON A REGULAR BASIS BY XDA DEVS THAT ARE INCLUDED IN THIS POST.

http://forum.xda-developers.com/showthread.php?t=1392310

Note : I AM NOT TAKING CREDIT OR DONATIONS OR ANY OTHER BIT OF THE GREAT PRO BONO WORK DONE ON A REGULAR BASIS BY XDA DEVS THAT ARE INCLUDED IN THIS POST.

Image via Wikipedia

Hi HTC users, there’s a great opprtunity to bring up to date your HTC device,thanks to Football, who is constantly contributing and updating all, or at least almost all HTC devices.

To choose your ROM head over to his thread and pick yours…

http://forum.xda-developers.com/showthread.php?t=1335368Note : I AM NOT TAKING CREDIT OR DONATIONS OR ANY OTHER BIT OF THE GREAT PRO BONO WORK DONE ON A REGULAR BASIS BY XDA DEVS THAT ARE INCLUDED IN THIS POST.

Do it at your own risk!!! Read complete guide once and then apply , if you skip any step then it can cause of bricked phone.
Follow this Guide on your risk and if your device gets damaged or bricked during the process, I am not responsible. Please follow steps carefully

Requirements

1. CF root modified kernel for XXKI3 firmware – Mirrors | Multiupload link
2. Download ODIN3-v1.85 from here  [use only this version otherwise it can bring serious problems]

Rooting Samsung Galaxy S II running Android 2.3.5 XXKI3 Firmware

1. Unzip CF Root kernel file and you will see a .tar file, it is possible that your pc shows .tar file as extractable archive but don’t extract it further. save this .tar file on safe place like desktop
2. Unzip Odin too and you will see two files first is .exe and second .ini 
3. Right click on Odin3 v1.85.exe and run it as admin
4. Check Auto Reboot , F.Reset Time and leave Re-partition unchecked.
5. Now click on PDA button and select CF-Root-SGS2_XX_OXA_KI3-v4.1-CWM4.tar 
6. After this, put your Samsung Galaxy S 2 in download mode.
7. To do that Switch off your phone
8. and press and hold volume down and middle key ,while holding both keys press power on key (don’t leave until it boots in download mode)
   if your phone is unable to boot in download mode don’t proceed to next step ,please try again until it boot in download mode
9. Once your phone is in download mode, you can connect your phone to the computer via USB.
10. Just after connecting you will ID COM box in Odin will turn yellow and in message box ADDED appears
11. Click on the Start button and wait for the kernel flashing process to complete.
12. During this process don’t stop Odin and don’t turn off phone.
13. Once the process is over, your phone will reboot automatically

How to remove yellow warning triangle

1. Download Stock kernel of XXKI3 | Password: intratech@XDA
2. Extract it by double clicking on it ,you will get .tar file
3. Now flash this .tar file on your phone , flashing procedure is same as above. you have to use kernel .tar file instead of cf root .tar file

Do it at your own risk!!! Read complete guide once and then apply , if you skip any step then it can cause of bricked phone.
Follow this Guide on your risk and if your device gets damaged or bricked during the process, I am not responsible. Please follow steps carefully

If ready then let’s get do it :
1. Go to Settings – Applications – Development and enable usb debugging
2. If you have rooted phone or using any custom ROM then you will have to clear cache and wipe data which can done by booting your phone in recovery mode and select Wipe data/factory reset and also select wipe cache partition
3. Download ODIN3 V1.83 ( I used v.1.85 and its fine) – it is a tool that is used to flash firmware on your phone
Drivers – Download and install drivers that are required to detect your phone by pc
Download Firmware for your phone from www.Samfirmware.com
Download .PIT File
4. Installing Firmware
If you have KIES installed skip next step
Extract SAMSUNG_USB.rar and install drivers on pc
Extract Firmware files on safe place, you will get some .tar file so please don’t extract .tar files [Password= samfirmware.com]
Run Odin3 v1.83.exe by right click and select run as admin

After extracting Firmware – VERY IMPORTANT

* If you got three or more files then Select Re-Partition , Auto Reboot and F.Reset Time

* If you got only single file then select Auto Reboot and F.Reset Time

Select .tar files from firmware folder,

* If you got three or more files then
Click on PIT and Select .pit file
Click on PDA and Select .tar file with CODE / PDA in the name
Click on PHONE and Select .tar file with MODEM in the name
Click on CSC and Select .tar file csc / csc-multi in the name
(See Image below carefully to understand which files to select)

* If you got only single files , then

Click on PDA and select single .tar file

Switch off your phone
Now boot it in download mode (press & hold volume down and middle key and while holding both press power on key)

When entered in download mode connect your phone to pc with usb cable
You will see ID:COM section turn yellow and in message boxes “ADDED” appears, that means your phone is ready to start flashing process

Now Click on “START” Button

Do not disconnect the cable or turn off the device, it will reboot when it finishes.
Congratulations you have successfully installed firmware on your Samsung Galaxy S 2, Now last step left is clearing cache data.
Boot your phone in recovery mode (press and hold VOLUME UP and MIDDLE KEY ,while holding both press POWER ON)
In recovery mode touch screen will not work so use volume UP and Down navigate through options and MIDDLE KEY to confirm
choose “wipe cache partition” from menu
it will clear the cache data
now select reboot system now

(Big thanks to Kuldeep singh for this tutorial and as always XDA-DEVELOPERS.COM

Then type “secret” sequence: □ ← ← □ ← □ □ ← on lock screen of your phone.

(This works only on stock ROM’s)

First off you need to create a Gold Card
Use the memory card that came with the phone (I think is somehow linked to phone)!

Install Goldcard helper from market, run it and copy the CID for MMC2

This number has already been reversed so go to here, fill out the required fields.

That will then email you an image file. You can then using Gold Card Tool flash your image file to your phones SD card via the phones USB cable.

Next for the actual downgrade
You’ll need this unzipped

in a command prompt, goto the directory you unzipped to
connect the phone via USB

then:

adb push misc_version /data/local/tmp
adb push GingerBreak /data/local/tmp
adb shell chmod 777 /data/local/tmp/misc_version
adb shell chmod 777 /data/local/tmp/GingerBreak

This copies the files to the phone and changes the permissions so they will function

adb shell

This will enter the terminal for the phone

./data/local/tmp/GingerBreak

This will then temp root the phone you should now have # at the terminal prompt instead of $, which means you have higher privileges

From this point you can then run misc_version (Thanks to Blezz for the version number) This changes the version reported by the phone to 1.27.405.6, you cannot check this on the phone tho, as it will still report the other number.

cd /data/local/tmp
./misc_version -s 1.27.405.6

From here you can then install the update/downgrade from the exe, no need to dump zip files or anything. As with anything here, results may vary and I won’t be buying new hardware if it breaks yours! But it works a treat on mine. 

Note #1: best ROM is RUU_Saga_HTC_Europe_1.28.401.1_Radio_20.28b.30.0805U_38.03.02.11_M_release_177977_signed , as it’s generic version for European market. All european languges supported.

Note #2 : keep your “gold card”, don’t format it as it will be needed for future updates (OTA or RUU).

(HUGE thanx goes to sonikz & newrad67 from xda-developers.com for this perfect and easy guide).