Factory Reset Code:
Open dialer, type in the following *#*#7780#*#*.
Another way is to open up settings and click on Restore > Factory Reset.
Reinstall Firmware:
You can reinstall your device’s firmware by typing in *2767*3855#.
You can also use a third party software on your computer to connect your phone and install new firmware.
Enable Testing Services:
This is commonly used for testers and android programmers.
Activate your Testing Services Mode by typing *#*#*#*#197328640 into your dialer.
Once you’ve done this, open the settings page to find the new Testing Menu.
Camera Information:
To find the type of camera on your phone, type in *#*#34971539#*#*.
Backing Up Media Files:
You can create backup files of your media files by using your phone’s dialer. Type *#*#*273 283 255* 663 282*#*#*.
Google Talk Monitoring Service:
Google is constantly listening. You can open up the monitoring service by typing in *#*#8255#*#*. There you’ll find what data Google really has on you.
Battery Status:
While the top-right part of your screen displays the battery status, you can also see more information by typing in *#0228#.
Encryption Information:
You can see the encryption type your phone is using by entering *#32489#.
Data Usage Statistics:
Check your true data usage by typing *# 3282 * 727 336*#.
3D Testing:
This may not work on all devices, but you can test out your 3D settings by typing in 3845 #*920#. This will show you if your devices are capable of rendering 3D modules.
WLAN Testing:
You can check the status of your Wireless Lan network settings by typing in 526#*#*#*#* or 528#*#*#*#*.
GPS Testing:
You can perform a full GPS test to see how accurate your GPS settings are. GPS isn’t always 100% dead on target. Just run the test *#*#1575#*#*
Bluetooth Testing:
Ever wondered why your Bluetooth settings are dropping connections? Maybe you can’t connect as quickly as you once could? Test out your Bluetooth for potential issues, and to see what type of Bluetooth hardware you’re using. Simply type *#*#232331#*#* into the dialer pad.
Checking FTA Software:
If you wanted to look at your device’s firmware to see the type of software used, type *#*#1111#*#*.