[LG Optimus L90] meer_mortal:
Best Hidden Android Secret Codes

*#*#778O#*#* = Factory Data Reset

*#*#I472365#*#* = Quick GPS Test

*#*#0673#*#* OR *#*#0289#*#* = Audio Test

*#*#2664#*#* = Touch Screen Test

#’#273283*255*663282*#*#* = Backup Media Files

*#*#0283#*#* = Packet Loopback Test

*2767*3855# = Reinstalls The Phones Firmware & Format Your Phone

*#*#232339#*#* OR *#*#526#*#* = wireless Lan Test

*#*# 1575#*#* = Different GPS Test

*#*#4636#*#*‘ = Complete Information About your Phone

*#*#2663#*#* = Touch Screen Version

*#*#232337#*# = Displays bluetooth Device Address

*#*#4986*2650468#*#* = PDA, Phone. Hardware, RF Call Date

*#*#44336#*#* = Displays Build Time

*#06# = Displays IMEI Number

*#*#8255#*#* = Google Talk Service Monitoring

*#*#I I I I#*#* | *‘#*#2222#*#* = FTA Software Version FTA | Hardware \/Version

*#*#3264#*#* = Rom version

*#*#23233I#‘*#* = bluetooth Test

*#*# 1234#’#’ = PDA and Phone Firmware Info

*#*#0*#*#*= LCD Display Test

*#*#0842#*#* Vibration and Backlight Test

*#*#0588#*#* = Proximity Sensor Test

*#*#232338#*#* = Wi-Fi Mac Address

*#*#7262626#*#*= Field Test

*#*#34971539#*#* = Camera Update

*#*#19732840#*#* = Enable Test Mode

*#06# – IMEI number

*#0*# – Enter the service menu on newer phones like Galaxy S III

*#*#4636#*#* – Phone information, usage statistics and battery

*#*#34971539#*#* – Detailed camera information

*#*#273282*255*663282*#*#* – Immediate backup of all media files

*#*#197328640#*#* – Enable test mode for service

*#*#232339#*#* – Wireless LAN tests

*#*#0842#*#* – Backlight/vibration test

*#*#2664#*#* – Test the touchscreen

*#*#1111#*#* – FTA software version (1234 in the same code will give PDA and firmware version)

*#12580*369# – Software and hardware info

*#9090# – Diagnostic configuration

*#872564# – USB logging control

*#9900# – System dump mode

*#301279# – HSDPA/HSUPA Control Menu

*#7465625# – View phone lock status

*#*#7780#*#* – Reset the /data partition to factory state

*2767*3855# – Format device to factory state (will delete everything on phone)

##7764726 – Hidden service menu for Motorola Droid

*#*#7594#*#* – Enable direct powering down of device once this code is entered

*#*#273283*255*663282*#*#* – Make a quick backup of all the media files on your Android device

*#*#232338#*#* – Shows Wi-Fi MAC address

*#*#1472365#*#* – Perform a quick GPS test

*#*#1575#*#* – For a more advanced GPS test

*#*#0283#*#* – Perform a packet loopback test

*#*#0*#*#* – Run an LCD display test

*#*#0289#*#* – Run Audio test

*#*#2663#*#* – Show device’s touch-screen version

*#*#0588#*#* – Perform a proximity sensor test

*#*#3264#*#* – Show RAM version

*#*#232331#*#* – Run Bluetooth test

*#*#232337#*# – Show device’s Bluetooth address

*#*#7262626#*#* – Perform a field test

*#*#8255#*#* – Monitor Google Talk service

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

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

*#*#2222#*#* – Show FTA Hardware version

*#*#44336#*#* – Show Build time and change list number

*#*#8351#*#* – Enable voice dialing log mode, dial *#*#8350#*#* to disable it

##778 (+call) – Show EPST menu

These codes are specific to HTC devices only:

*#*#3424#*#* – Run HTC function test program

*#*#4636#*#* – Show HTC info menu

##8626337# – Run VOCODER

##33284# – Perform field test

*#*#8255#*#* – Launch Google Talk service monitor

##3424# – Run diagnostic mode

##3282# – Show EPST menu

##786# – Reverse Logistics Support

Source - http://www.techgrey.com/2014/10/best-hidden-android-secret-codes.html?m=1#