Hacking your Android OS device, also known as "rooting," can be a great way to unlock new features that your wireless carrier nixed or Google failed to include. Root your Android handset, and you'll be able to control every aspect of it--from the processor speed to the user interface--just as you can control your PC.
WARNING: PCWorld is not responsible for any broken or bricked phones that result from this how-to. Rooting your phone will most likely void your phone's warranty, and if something goes wrong it may very well turn your phone into a pricey paperweight. Proceed at your own risk.
Step 1: Getting Root Access
The first step toward total control of your Android device is obtaining root access. Unfortunately, my favorite method to gain root on an Android device, the Easy Root app, no longer works as well as it once did, due to recent Android updates. Thankfuly, the basic process remains the same--you'll just have to roll back to a slightly older Android release, after which you can install a custom ROM of your choice.
Before you get started, note that rolling back your device to a previous version of the Android OS will likely erase any data not on the SD Card or stored on Google's servers.
I'll use the Motorola Droid and Windows as an example, along with instructions from the CyanogenMod Wiki. First, download and install RSD Lite and the Motorola USB drivers, and then download a copy of the SPRecovery SBF image file. Connect the Droid to a Windows computer via USB, and turn off the device. Turn it back on while holding down the power button and the up key on the directional pad to boot into Recovery Mode.
Once the phone has booted, run RSD Lite (right-click the icon in Windows and choose Run as administrator), select the SPRecovery SBF image, and click Start. RSD Lite will apply the recovery image and reboot the Droid. If you do not receive a 'Pass' message from RSD Lite after the device has rebooted, apply SPRecovery with RSD Lite again.
The next step is to install a prerooted version of Android OS 2.1 on the Droid. To do so, you'll need to download the Android OS image and rename it to update.zip. Connect the Droid to your PC via USB, mount the device, and copy update.zip to the root of the SD Card. Unplug the USB cable, power off, and then reboot the Droid while holding the "x" key.
When the phone has booted, use the volume keys to navigate and the camera button to select Wipe data/factory reset. Choose Wipe cache partition, then Install, and Allow update.zip installation. The update will now be applied, after which the Droid will reboot into a rooted version of Android 2.1.
Don't have a Droid? Not to worry: You can find detailed instructions for gaining root on a number of Android devices on the CyanogenMod Wiki.
Step 2: Replacing the ROM
After you have updated your device to a rooted version of Android 2.1, you'll most likely want to upgrade again to a more up-to-date third-party ROM. One of the most popular options is CyanogenMod.
CyanogenMod has ROMs available for many phones, and typically includes features left out of the stock ROMs that Google distributes. For example, CyanogenMod adds tethering via Wi-Fi or Bluetooth, so you can share your phone's Internet connection with other devices. Also, CyanogenMod lets you use ROMs of newer Android OS releases on older or unsupported devices, such as Froyo on the G1.
CyanogenMod isn't the only aftermarket Android ROM option. Other alternatives offer different combinations of features, including additional home screens and widgets, more connectivity choices, and the ability to get the most out of the multitude of apps on the Android Market that require root access to your device.
Additionally, you can find ROM options for boosting performance on specific devices at the expense of extra features--but be sure to double-check compatibility with your device before installing a performance ROM.
After rooting your device, the easiest method to replace your ROM is to use the ROM Manager app available in the Android Market (in both free and paid versions) to install ClockworkMod Recovery. Download, install, and open the ROM Manager app, select Flash ClockworkMod Recovery, choose your device, and grant root privileges when asked.
Reopen ROM Manager, select Download ROM from the main menu, and pick the ROM you'd like to install. In our example, we're installing the most recent version of CyanogenMod, but always be sure to check the Google Apps box; otherwise you'll be left without apps such as GMail.
Once the ROM finishes downloading, grant root privileges if asked again, and select both Backup Existing ROM and Wipe Data and Cache. The Droid will install the CyanogenMod ROM and reboot.