Before you can root your Nexus One phone or install new ROMs such as Cyanogen’s mod, most likely your will need to unlock your bootloader.
*Unless you bought an unlocked phone straight from Google without T-mobile and whatnot, you will have a locked bootloader.

But don’t worry, unlocking your bootloader is easier than it sounds, actually it’s just a one-line command.

*Note – This will erase all your settings, it won’t touch your camera images and the SD card but it will erase all your settings so backup any data before!!!

First Step – How to Install Android SDK and USB drivers!

Before anything, you will need to download and install the Android SDK and USB drivers.  What this does is install all the basic software you need plus ability for your computer to talk to your Nexus One via USB driver.

Is this hard?  No but I think it might be helpful for me to actually walk you through it because I installed everything and you don’t need to waste time installing everything.

1. Download the Android SDK for your platform. (Windows/Linux/Mac).

2. Run SDK Setup.exe (or similar for other OS) then select “Android SDK Tools”, “SDK Platform Android 2.1″, and “Usb Driver package” as shown here:

That’s all you really need so accept the ones I’ve mentioned and reject others so you don’t waste time downloading everything.

3. Once you’ve installed the Android SDK and USB drivers, you will need to make sure your USB drivers are installed.

What I found with my Windows 7 laptop is that the USB drivers don’t install themselves automatically.  What you can do is install them manually.

You can check if your Android USB drivers are installed by going to “Printers & Devices” on Windows 7.  (and I think you can check Device Manager for other versions of Windows).

If you see Android device with a warning or question mark (like seen in below screenshot), simply do right click then click properties.  You should then be able to find “Update Driver” where you can update it with the usb drivers found in your Android SDK directory. (\usb_driver)

By the, your Android SDK directory is where you unzipped the Android SDK file.

For me, this was under C:\Users\max\Downloads\android-sdk_r04-windows\android-sdk-windows\usb_driver.  It took me like an hour to realize that the SDK is downloaded to the original unzipped directory, not under Program Files directory.

Once you have the USB drivers and your computer recognizes your Nexus One phone, you should be good to go.  By the way, you need to connect your Nexus One phone to your computer via a USB cable if you want to see it, duh! (just in case)

You should see something like this when the Nexus One driver is installed correctly:

Step 2 – How to Unlock Bootloader on your Nexus One!

1. Download the fastboot bootloader unlocker here.

2. Unzip it to a directory such as C:\fastboot.

3. Open up command prompt by typing “cmd” under Start->”Search Programs and Files” in Windows 7 and I think “cmd” under Start->Run for Windows XP.

4. Once in the command prompt, change directory to where you unzipped the fastboot bootloader unlocker.  e.g. cd c:\fastboot

5. At this point, power off your phone and then press the power button while holding down the trackball button. You should boot into the “bootloader”.  If you see bunch of Android characters on skateboards, you are in the right place.

Your Nexus One should look somewhat like below screenshot:

6. With your Nexus One in bootloader mode and connected to your computer via USB cable, go back to the command prompt and type “fastboot-windows oem unlock”.

For mac, “./fastboot-mac oem unlock” and linux, “./fastboot-linux oem unlock”

7. If your phone connects, you should see the following screen on your Nexus One:

8. Select “Yes” to void your warranty. (by pressing the Volume Up button then pressing the Power button)  Of course, if you don’t want to void your warranty, you should stop here but where’s the fun in that?

Once you have unlocked your Nexus One, you should see an unlocked “lock” icon whenever you start your Nexus One from now on.

Congratulations, you have just unlocked the bootloader on your Nexus One, hurray!

Here’s a video I took while unlocking the bootloader on my Nexus One (After step 6) for the first time in my car. (Yes, I was so excited, I did it in my car!)

Next, we will show you step-by-step guide on how to install the Cyanogen mod and enjoy a faster/better Nexus One plus you will be able to enjoy the WiFi tethering app.

Many thanks to this guide here Modaco.com, which I originally used for this guide.

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