[HTC EVO 3D] gothir:
This is a guide to changing your PRL...no root required.

Where I work has an absolutely horrible Sprint 3g connection...lucky if it breaks 100kbps...so I use a modified PRL while I am at work to roam on Altell/Verizon towers. If you have the same problem as me then read below on how to change your PRL.

This is my first guide so let me know if you see anything I can do to improve it and be gentle =P. I couldn't have made this guide without Leviuqse's Epic 4g PRL guide HERE and yoboii23's guide to getting your MSL and drivers setup HERE. I was able to use information from both of their guides to help get this method working on my Evo 3d. This process seems long but it actually takes less than 1 minute to do once you have everything setup.

Disclaimer: Changing your PRL can build up a lot of roaming data/calls if you use a modified PRL/other carrier PRL if you are not careful. Use another PRL at your own risk. Don't play with the settings in QPST.

Requirements:

1. HTC Diagnostic Drivers installed

2. MSL for your phone

3. QPST installed...I tested this method with QPST 2.7 build 323 and QPST 2.7 build 366.

4. PRL file of your choice

Step 1 - Install your HTC drivers and acquire your MSL. yoboii23 over on XDA wrote a great guide on installing the drivers and getting your MSL HERE. Follow those instructions before moving to the next step.

Step 2 - Google and install QPST...I tested this method with build 323 and build 366. X-drivers has the software listed as freeware but I am not 100% sure it is so I will not post any direct links.

Step 3 - Find what PRL you want to use and put it in a folder on your computer. I am using a modified PRL created by techknowfile on XDA that is located HERE. This PRL works great for me but your mileage may vary...try out a few PRLs and see what works best for you.

Step 4 - Turn off USB debugging on your phone...go to settings > applications > development > uncheck USB debugging

Step 5 - Open the dialer on your phone and enter ##3424#

Step 6 - Connect your phone to the computer and select Charging only if prompted.

Step 7 - Open QPST Configuration wherever you installed it.

Step 8 - Click on "Add new port"

Step 9 - Uncheck "Select Serial and USB/Diagnostic Ports Only"

Step 10 - Select your phone on the list and hit OK.

Step 11 - Select your phone on the list.

Step 12 - Click on the "Start Clients" tab at the top and select "Service Programming"

Step 13 - Select your phone on the list and hit OK

Step 14 - Click on "Read from Phone' in the bottom left

Step 15 - Enter your MSL when prompted and hit OK

Step 16 - Click on the "Roam" tab then click "Browse" and navigate to your PRL file. After selecting your PRL click "Write to Phone".

Step 17 - Your phone will reboot at this point and you will see a couple popups on your computer that you can just hit OK to close. Let your phone reboot and don't close QPST until it is finished writing to your phone.

Step 18 - The PRL should be written to your phone now. You can verify it by going to settings > about phone > software information > more > PRL Version. If you want to switch back to a stock Sprint PRL then all you need to do is go to settings > system updates and click Update PRL.