With each new firmware release for Samsung’s Android devices, there usually comes along a new radio/modem version, usually with improvements to signal strength or mobile data download speeds, but sometimes they also work worse than the previous ones for some. Hence, it’s always a good thing to try different modems and see which one works best for you.

With a lot of Android 4.1 Jelly Bean firmware leaking for the T-Mobile Galaxy S3 in the past few days, XDA Senior Member DocHoliday77 decided to put together all available modem versions for the device in one easy to access place, which can be installed via a custom recovery like ClockworkMod or TWRP recovery.

So if you’re looking to try out different modem versions to see which one works best for you, follow the guide below to find out how the modems can be installed.

Compatibility

This hack and the guide below are compatible only and only with the T-Mobile Galaxy S3, model number T999. It’s not compatible with other US variants or other devices. Check your device’s model number in Settings » About phone.

Warning!

The methods and procedures discussed here are considered risky and you should not attempt anything if you don’t know completely what it is. If any damage occurs to your device, we won’t be held liable.

How to Install Modem/Radio on T-Mobile Galaxy S3

  1. Important! Make sure you are on a T-Mobile network before attempting this.
  2. Make sure you have ClockworkMod recovery or TWRP recovery installed on the phone. You can use this guide to install ClockworkMod recovery.
  3. Download the modem you want to try out from the source page.
  4. Copy the downloaded modem file to the internal storage.
  5. Now, boot into ClockworkMod (or TWRP) recovery. To do that, turn off your phone. Then, hold down Volume Up, Home and then the Power buttons together until the screen turns on, then let them go. The phone will boot into ClockworkMod recovery in a few seconds.
    In recovery, use the volume buttons to scroll up/down and the home button to select an option.
  6. Select install zip from sdcard, then select choose zip from sdcard. Scroll to the modem file on the SD card and select it. Confirm installation by selecting Yes on the next screen (for TWRP recovery, select Install, then select the modem file) . The modem will start installing.
  7. After the installation is complete, go back to the main recovery menu and select reboot system nowto reboot the phone. (or press the Reboot system button in TWRP recovery).
  8. Once the phone boots up, the new modem will be installed on your T-Mobile Galaxy S3. Try it out for a while (preferably a day or two) to see how it works regarding signal strength or download speeds. Then, download another modem and repeat the procedure to install it and in this way try out different modems.

The modem/radio of your choice is now installed on your T-Mobile Galaxy S3 and you can try it out to see how it works for you. Be sure to try all the modems a bit to see which one works best.