Jeremy Sikora at AndroidCentral Forum has posted a very useful and easy guide to help you in installing custom ROMs onto your Nexus One phone. Its an easy guide that would be even useful for a beginner. I am posting the text from the original post here as it is you can read it here or can see it at the forum on writer’s original thread, but before you start want to warn you to be careful and don’t try this if you don’t have sufficient knowledge about it as it could result badly for your data, warranty and keep it in mind that this procedure can not be undone once performed.
So lets get started here
Unlocking the Bootloader
1.) Make sure your device is off. With your device connected to your computer enter fastboot mode by pressing the power button down while holding down the trackball.
2.) Now download and extract fastboot to your desktop.
3.) Windows Users: Enter bootloader mode by opening a command prompt and browse to the directory containing the fastboot files that you just extracted to your desktop, then type fastboot-windows oem unlock [Enter]
Mac Users: Enter bootloader mode by opening a terminal window and browse to the directory containing the fastboot files that you just extracted to your desktop. Assuming you extracted fastboot to your desktop, then Terminal commands to get to folder are as follows: cd ~/desktop/fastboot [Enter], then type ./fastbook-mac oem unlock [Enter]
Your bootloader is now unlocked.
Rooting your Nexus One
1.) Now we will gain root access to your device. Download this Superboot.zip file and extract it to a new folder on your desktop.
2.) Put your device back into fastboot mode as you did in step 1 of unlocking your bootloader.
3.) Windows Users: Double-click the install-superboot-windows.bat from within the new Superboot directory on your desktop.
Mac Users: While in the directory of 1.1-nexusone-superboot on your desktop type the following: chmod +x install-superboot-mac.sh [Enter] Then type ./install-superboot-mac.sh [Enter]
Bingo, your Nexus One is now “rooted”…
Flashing the RA-Nexus Recovery Image [1.6.2] to your Nexus One
1.) First thing you need to do is download Amon_RA’s latest recovery image. As of writing this it is v1.6.2.
2.) Now you need to place that file into the root of your 1.1-nexusone-superboot directory that should still be on your desktop from the steps above.
3.) Now with your device off, connect it to you computer.
4.) Boot your device into fastboot mode by holding the power button down while holding the volume rocker down. Then press the power button down to select fastboot usb selected.
5.) Windows users: Launch the Command Prompt and change directories to 1.1-nexusone-superboot folder. Type the following: fastboot-windows flash recovery recovery-RA-nexus-v1.6.2.img and hit enter.
Mac users: Launch the Terminal and change your directory to 1.1-nexusone-superboot folder on your desktop. Type the following: ./fastboot-mac flash recovery recovery-RA-nexus-v1.6.2.img and hit enter.
The 1.6.2 recovery image is now loaded onto your Nexus One.
You are now ready to do a Nandroid Backup and install a custom ROM of your choice.
1.) With your device powered off hold down on the volume down rocker while pressing the power button. From there select “recovery”.
2.) Once in recovery select backup/restore and choose Nand backup.
When that is completed you now have a backup image saved on your SD card in case you ever need to go back to the normal ROM.
3.) Now from the recovery menu select Wipe and then Wipe data/factory reset.
4.) Once the wipe is completed select Flash zip from sdcard to select the ROM you wish to install.
5.) Once the flashing process is completed simply reboot and enjoy your freshly flashed Nexus One!
[Via Forums.Androidcentral]
