How To hard reset the Google Nexus One

[cable man]

With the phone off, hold the Volume Down button and press and release the Power button.
You'll boot into the menu you see above with the little skateboard guys. Select Clear Storage from the list by pressing the Volume Down button.
Press the Power button, and confirm by pressing Volume Up.
Sit back while your phone reboots in its virgin state.
With the phone off, hold the Volume Down button and press and release the Power button.
You'll boot into the menu you see above with the little skateboard guys. Select Clear Storage from the list by pressing the Volume Down button.
Press the Power button, and confirm by pressing Volume Up.
Sit back while your phone reboots in its virgin state.

[tiger56]

FYI These codes have been obtained by decoding various .apk files present in the phone firmware.
*#*#4636#*#*
This code can be used to get some interesting information about your phone and battery. It shows following 4 menus on screen:

Phone information
Battery information
Battery history
Usage statistics
*#*#7780#*#*
This code can be used for a factory data reset. It'll remove following things:

Google account settings stored in your phone
System and application data and settings
Downloaded applications
It'll NOT remove:

Current system software and bundled applications
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:

Update camera firmware in image (Don't try this option)
Update camera firmware in SD card
Get camera firmware version
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.
WLAN, GPS and Bluetooth Test Codes:
*#*#232339#*#* OR *#*#526#*#* OR *#*#528#*#* - WLAN test (Use "Menu" button to start various tests)
*#*#232338#*#* - Shows WiFi MAC address
*#*#1472365#*#* - GPS test
*#*#1575#*#* - Another GPS test
*#*#232331#*#* - Bluetooth test
*#*#232337#*# - Shows Bluetooth device address
*#*#8255#*#*
This code can be used to launch GTalk Service Monitor.
Codes to get Firmware version information:
*#*#4986*2650468#*#* - PDA, Phone, H/W, RFCallDate
*#*#1234#*#* - PDA and Phone
*#*#1111#*#* - FTA SW Version
*#*#2222#*#* - FTA HW Version
*#*#44336#*#* - PDA, Phone, CSC, Build Time, Changelist number
Codes to launch various Factory Tests:
*#*#0283#*#* - Packet Loopback
*#*#0*#*#* - LCD test
*#*#0673#*#* OR *#*#0289#*#* - Melody test
*#*#0842#*#* - Device test (Vibration test and BackLight test)
*#*#2663#*#* - Touch screen version
*#*#2664#*#* - Touch screen test
*#*#0588#*#* - Proximity sensor test
*#*#3264#*#* - RAM version
NOTE: All above codes have been checked on Google Android phone Samsung Galaxy I7500 only but they should also work in other Google Android phones.

------------------------------------------------------------

[tiger56]

Universal Androot v1.5.3(5 seconds root)


This is software written by the Taiwanese people, I did not test it, already have rooted xperia x10!....Use at own risk

v1.5.3 Update:

Add drop-down menu select modify records required Superuser version, mobile version of the program will automatically make the default option, but if the root problem after use, you can choose "Do not install Superuser" modified script file exists and determine permissions fixes root / unroot open after Wifi power problem.
This process is called "Universal Androot", is to exploit the process through the back door to write UI form, so users can just click the button Root, but not what each Android phone can be successful, no way, as Samsung i9000. If concerned about undermining the warranty, you can press the "UnRoot", you can restore the original state.

Supported:

Google Nexus One (2.2)
HTC Hero (2.1)
HTC Magic (1.5)
Dell Streak (2.1)
Motorola Milestone (2.1)
Motorola XT701
Motorola XT800 (2.1)
Motorola ME511
Sony Ericsson X10 (1.6)
Sony Ericsson X10 Mini Pro (1.6)
Acer Liquid (2.1)
Vibo A688 (1.6)
Lenovo Lephone (1.6)

Not supported:

Samsung i9000 (Galaxy S)
Samsung i6500U
Motorola ME600 (1.5)
HuaWei U8220
HTC Desire / Legend / Wildfire (/ system can not write)