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Rooting Your Android Based T-Mobile G1: Part 3, Upgrading the Radio, SPL, and ROM

written by: Christopher Earle•edited by: Simon Hill•updated: 7/6/2011

Now that you have a rooted G1 with a custom recovery image, you can install anything from the latest official T-Mobile ROM to mods from people like Cyanogen, Jesusfreke or Haykuro. Most people install the Cyanogen mod, it contains more custom features than the other two.

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    Now that your phone is rooted, it is time to upgrade your system from Android 1.0 and the RC29 version of the radio. Replacing the phone's Secondary Program Loader (SPL) is also recommended, but not required. Upgrading the SPL will allow for more efficient use of the memory on your Android based T-Mobile G1 with Google. In addition, an upgraded SPL is required by some ROMs.

    Please read through all three sections of this article and make sure you understand all the steps before proceeding.

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    Upgrading the Radio Image

    To upgrade your radio image, do the following:

    1. Download the latest radio image to your computer. At the moment, that image is
    2. Copy that file to your SD card's root.
    3. Turn off your phone.
    4. Make sure your SD card is in the phone and power the phone on while holding down the Home button.
    5. Once the recovery screen loads, select apply any zip from sd.
    6. Press Home to write the new radio image to your phone.
    7. When the image is installed, press Home and Back at the same time to re-boot your phone.

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    Verify the Installation

    To verify the proper installation of the new radio image, do the following:

    1. Press the Menu button.
    2. Select Settings.
    3. Scroll to the bottom of the screen and select About Phone.
    4. Look for the Baseband version. It should be, or any more current version that you installed above.

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    Flash a New SPL

    To install a new SPL, you must be running the latest radio image as detailed above. Although replacing your SPL is not always necessary, it may be required by some ROMS. Another advantage of flashing a new SPL is that it will increase your available app space by around 20 MB. After installing this file, your phone will not boot. Once you have followed these steps, you will have to install a new ROM for your phone to work. If you have NOT been using a card reader, make sure you copy the two files needed in the next section to your SD card before completing these steps. After this procedure, your phone will not connect to your computer until you have completed the next procedure.

    To flash a new SPL, do the following:

    1. Download the latest version of the SPL. That is currently 1.33.2005 and is named, but may be upgraded.
    2. Copy the file to the root of your SD card.
    3. Turn off your phone.
    4. Ensure that your SD card is in your phone.
    5. Enter the phone's recovery mode by pressing the Power button while holding down Home.
    6. When Cyanogen's recovery screen loads, select apply any zip from sd. Install the SPL zip.
    7. Once the installation has completed, remove your SD card and place it in a card reader.

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    Installing Your New ROM

    Now that you have a new SPL flashed, you must install a new ROM for your phone to work. Although Haykuro and Jesusfreke both have excellent ROMs, many people install Cyanogen's ROM because it supports advanced features like running apps from your SD card (Note: This requires a very fast, very reliable SD card, and even then can sometimes result in complete failure that requires a complete rebuild of your phone's software).

    Cyanogen was recently involved in a legal dispute with Google over his inclusion of Google code in his mods. Google and Cyanogen appear to have come to an agreement that doesn't violate Google's intellectual property, but that results in you having to now flash your new ROM in two steps.

    Because Cyanogen's ROMs are frequently updated and the exact installation procedure may change, it is a very good idea to frequently check the Cyanogen website frequently.

    An Android 1.6 home screen with the Cyanogen mod. To install the latest Cyanogen mod on top of the official Google Android 1.6 release, do the following:

    1. Download the Android 1.6 Recovery Image. The current file is
    2. Download Cyanogen's modifications, the current version is 4.1.999. The current version is at the bottom of the Cyanogen's website.
    3. Put both images in the root of your SD card.
    4. Re-boot into recovery mode, if you aren't already there, by pressing Power while holding down Home.
    5. Wipe the device using the Wipe menu selection on the recovery screen. You must wipe the phone before installing these zip files for Google's apps to work right.
    6. Install the recovery image first.
    7. Watch the installation carefully. On some phones, the installation will automatically reboot the phone. You must be ready to hold down the Home button to re-enter the recovery screen.
    8. Apply the file to the phone. These are the Cyanogen mods. If you downloaded a more recent version, apply that version.
    9. Reboot your phone.
    You now have a rooted phone running the latest Cyanogen mod.

Rooting & Flashing Your Android Based T-Mobile G1 With Google

Rooting your G1 and installing a modified ROM, like those from Cyanogen, Jesusfreke or Haykuro, will enable many features not included in the native T-Mobile build. A rooted phone also gives you access to a number of applications, like screen capture apps.
  1. Rooting Your Android Based T-Mobile G1: Part 1, Downgrading Your Radio
  2. Rooting Your Android Based T-Mobile G1: Part 2, Rooting & New Recovery Image
  3. Rooting Your Android Based T-Mobile G1: Part 3, Upgrading the Radio, SPL, and ROM