[HTC EVO 3D] felacio:
1st time making a guide (That I can remember) so bare with me.

DISCLAIMER: While I have done this on my phone and it worked without issue, I can not be held responsible for any wrong doing, damage, etc. done to your device. Follow this guide at your own risk!

Requirements:

Evo 3D running CM10 (duh)

PC with WinXP/Vista/7 (no clue if this works on 8)

Your MSL number. Use MSL Reader from Play Store

QPST Configuration Software

Terminal Emulator from Play Store

a PRL file.

(Optional, not required if using Terminal Emulator) Root Explorer

First things first! to kick the phone into Diagnostic Mode: on your phone, open Terminal Emulator and type

su
echo 1 > /sys/class/android_usb/f_diag/on

Alternatively, if you have Root Explorer, simply navigate to sys/class/android_usb/f_diag/ and edit the file named "on". In there, change the 0 to a 1 and save. This is EXACTLY like using the Terminal Emulator method above, so EITHER of these, not BOTH.

It won't look like anything happens on the phone, but this CAN'T BE SKIPPED!

If you haven't installed the HTC DIAG drivers yet, Continue: If you have and they are working properly, skip to step 9.

HTC Diag Drivers. Either 32-bit or 64-bit, depending on your OS.

Installing HTC DIAG Drivers:

1.) Make sure phone is in Android Debugging Mode (Settings > Developer Options > Android Debugging Mode)

2.) Plug your phone into your computer.

3.) Let windows install it's drivers, it should show that it couldn't automatically install one called "HTC DIAG." This is where we install them manually.

4.) Go to Control Panel > System and Security > Under System is a smaller option for "Device Manager"...click it.

5.) You should see the driver that didn't install properly already, a yellow exclamation mark called "HTC DIAG"

6.) Right-click HTC DIAG > Update Driver Software... > Browse my computer for driver software > Let me pick from a list... > Have Disk... > Browse... >

7.) Navigate to where you unzipped the HTC DIAG drivers, remember to go into the folder that matches your OS (32 vs 64) and select HtcUsbMdmV64.inf or htcdiag.inf.

8.) Install driver, and you mght need to reboot before they work properly. Now, when your phone is plugged in, it should recognize as "HTC Modem"

Flashing PRL with QPST

9.) Open "QPST Configuration" from PC (Start Button > type QPST into search bar )

10.) Select "Add New Port"

11.) Uncheck "Show Serial and USB/QC Diagnostic ports only" and the port your phone is currently plugged into should pop up. Select it and hit OK

12.) Make sure the port your phone is plugged into is highlight and on the menu bar click "Start Client" > SERVICE PROGRAMMING.

13.) Hit OK, as the only device showing should be your phone.

13.) A new window will pop up. Select the "Roam" tab. Near the bottom of the window click "Read from Phone" and input your MSL Code here.

14.) Hit the "Browse..." option and find the PRL you want to flash to your phone. Hit OK and press "Write to Phone" You will get an error, which is normal.

15.) Reset your phone, this is important and it happens automatically on HTC Sense ROM's for the changes to take effect. IT doesn't happen automatically on CM/AOSP ROM's so needs to be done manually.

16.) ENJOY! Yep, once it fully boots back up, go into Settings > About Phone > Status > scroll down to PRL Version and it should be the new one that you just flashed!

Just a note, I am running a "modified" version of CM10 not found here on XDA, So I can't verify it works with all other versions. But I don't think there should be a problem.