[EVO 4G Android Development] izzystylez:
Just found this out thought i'd share with the community. sorry if someone already posted this, i've never come across a method.

Yes you read right, How to change PRL on AOSP roms is very simple

Assuming you already have your MSL codes and know how to use QPST or CDMA Workshop, manually updating your PRL is very simple. No need for dual rom boot or flashing sense roms just to do this.

This simply enables Diagnostics mode which is accomplished on sense roms by ##3424#, once enabled it lets you use QPST or CDMA workshop or others.

Requirements.

If you commonly flash then you should already have these installed, if not they are easily attainable via a google search

* Your MSL number

* QPST or CDMA Workshop or other program

* HTC EVO diagnostic drivers installed

* Terminal Emulator

On AOSP

Simply pull up Terminal Emulator

type:

su

echo 1 > /sys/devices/virtual/usb_composite/diag/enable

This enables Diagnostics Mode, which enables us to use QPST :D

Open QPST Configuration

Select the "Ports" tab

Click "Add New Port"

Uncheck "Show Serial and USB/QC Diagnostic ports only"

Click on your device and hit OK

Highlight your phone on the "Ports" tab

Open up the "Start Clients" menu

Click on "Service Programming"

QPST Service Programming will open up and a "Phone Selection" window will appear: Click your phone if needed, and press OK

Now select the "Roam" tab and click on "Read from Phone" button

Enter your MSL, OK

Click on the "Browse" button and select the PRL file you want on your phone

Click the "Write to Phone" button next to the "read phone" button

Wait for it to finish writing to the phone. You might (read as most likely) get an error box, click OK on it.

Once all that is done, you can reboot your phone and enjoy the changed PRL without nandroiding, nand-restoring/flashing, etc. etc. :D

I just want to mention that the first time I did it, I lost my Mobile Data connection (3g) and after a reboot it was stuck on 1x. After another reboot, it was back to normal. But I believe that it was because I tried a verizon PRL that drops my service to almost 0.

End results​

Here is some general PRL info:

PRL Definition - (Preferred Roaming List)

The PRL is a list of information that resides in the memory of some kinds of digital phones. It lists the radio frequencies the phone can use in various geographic areas.

The part of the list for each area is ordered by the bands the phone should try to use first. Therefore it's a kind of priority list for which towers the phone should use.

The PRL helps determine which home-network towers to use, and also which towers belonging to other networks to use in roaming situations (areas where the home network has no coverage.) When roaming, the PRL may instruct the phone to use the network with the best roaming rate for the carrier, rather than the one with the strongest signal at the moment.

Since a PRL tells the phone "where" to search for a signal, as carrier networks change over time, an updated PRL may be required for a phone to "see" all of the coverage that it should, both with the home network and for roaming.

PRL Changelog

http://www.batonrougebroadband.info/

Thanks to original threads

http://xdaforums.com/showthread.php?t=1162091

http://xdaforums.com/showthread.php?t=1029900