Secret Codes - MMI USSD

Some interesting secret codes which can enable/disable lots of hidden settings in the mobile phone. These codes can also show many useful information about the phone. Now is not necessary to remember all those codes, they are just one finger tap away from you!
*** IMPORTANT! Some manufacturers not allow the use of these codes and they may not work on your device. By using secret codes you can change some of your device settings. Use at your own risk! ***
DISCLAIMER: This information is intended for experienced users. It is not intended for basic users, hackers, or mobile thieves. Please do not try any of following methods if you are not familiar with mobile phones. We'll not be responsible for the use or misuse of this information, including loss of data or hardware damage. So use it at your own risk.
What is USSD code
Unstructured Supplementary Service Data (USSD), sometimes referred to as "Quick Codes" or "Feature codes", is a protocol used by GSM cellular telephones to communicate with the service provider's computers. USSD can be used for WAP browsing, prepaid callback service, mobile-money services, location-based content services, menu-based information services, and as part of configuring the phone on the network.
If you want to know more information about it, please visit https://en.wikipedia.org/wiki/Unstructured_Supplementary_Service_Data
Some secret code example:
*#*#4636#*#* - This code can be used to get some interesting information about your phone and battery. It shows following 5 menus on screen:
1> Phone information
2> Battery information
3> Battery history
4> Usage statistics
5> Wifi information
*#*#7780#*#* - This code can be used for a factory data reset. It'll remove following things:
1> Google account settings stored in your phone
2> System and application data and settings
3> Downloaded applications
It'll NOT remove:
1> Current system software and bundled applications
2> SD card files e.g. photos, music files, etc.
PS: Once you give this code, you get a prompt screen asking you to click on "Reset phone" button. So you get a chance to cancel your operation.
*2767*3855# - Think before you give this code. This code is used for factory format. It'll remove all files and settings including the internal memory storage. It'll also reinstall the phone firmware.
PS: Once you give this code, there is no way to cancel the operation unless you remove the battery from the phone. So think twice before giving this code.
*#*#34971539#*#* - This code is used to get information about phone camera. It shows following 4 menus:
1> Update camera firmware in image (Don't try this option)
2> Update camera firmware in SD card
3> Get camera firmware version
4> Get firmware update count
WARNING: Never use the first option otherwise your phone camera will stop working and you'll need to take your phone to service center to reinstall camera firmware.
*#*#7594#*#* - This one is my favorite one. This code can be used to change the "End Call / Power" button action in your phone. Be default, if you long press the button, it shows a screen asking you to select any option from Silent mode, Airplane mode and Power off.
You can change this action using this code. You can enable direct power off on this button so you don't need to waste your time in selecting the option.
*#*#273283*255*663282*#*#* - This code opens a File copy screen where you can backup your media files e.g. Images, Sound, Video and Voice memo.
*#*#197328640#*#* - This code can be used to enter into Service mode. You can run various tests and change settings in the service mode.
Please share secret USSD codes you already know and I will update the application accordingly.
Enjoy and have a fun!

Actualización de Secret Codes 1.0.19

fix crash issue