[Windows Phone 7 Development and Hacking] hx4700 Killer:
I made this post here: http://xdaforums.com/showpost.php?p=15329491&postcount=5

Your device needs to already be dev unlocked and in NODO!!

Someone else has confirmed that you need diagnosis version is 1122.

1. Make a backup of your device. You can use my app for that if you wish: http://xdaforums.com/showthread.php?t=1103011

1.1 - Make a backup

1.2 - Make a backup

1.3 - Make a backup!!!!

Get the point? you CAN NOT get the official Mango update when its released without reverting to NODO so MAKE A DAMN BACKUP! I personally have 4 backups just in case!

2. I installed this unlock.xml: http://xdaforums.com/showpost.php?p=15316160&postcount=9

3. Install WP7 Root Toosl by Heathcliff .5 alpha from his thread: http://xdaforums.com/showthread.php?t=1021135

4. Load the root tools and using the explorer create a directory called provxml in the root of the drive if it doesnt already exist.

5. Using the root tools copy unlock.xml file from: Applications\Install\D19A80F2-1717..... (you may have to browse folders in that path) to the provxml folder at the root of the device. (I apologize but I don't know the exact path I believe it starts in the root but I would have to revert to nodo to know for sure as the root tools don't work in mango.

6. *OPTIONAL TEST* Once that file is there you can test it to be sure it works like I did by changing one of the unlock reg keys and applying the XML to confirm it changes back. I used the root tools registry editor part to browse to: "HKLM\Software\Microsoft\DeviceReg" I changed the value "PortalUrlProd" by adding random text as it should be clear/empty/null. Then I applied the xml by going to the diagnosis tools from my shortcut or by going to the phone app and then the keypad and typing: ##634#. Once in Diagnosis enter: *#9908# to get to the GPRS profiles. Tap the dropdown and you should see unlock in your list. Select unlock and then save at the bottom. It only takes a second and says success in the window below the dropdown. Now exit diagnosis and use the root tools again to confirm the registry value you set before is now cleared/empty/null. If that works you can proceed with confidence.

7. Perform the 2 step mango update from this link: http://windowsphonehacker.com/articles/get_the_mango_update_now._without_being_a_developer.-06-30-11

8. Once updated and in mango apply the xml by: going to the diagnosis tools from a shortcut or by going to the phone app and then the keypad and typing: ##634#. Once in Diagnosis enter: *#9908# to get to the GPRS profiles. Tap the dropdown and you should see unlock in your list. Select unlock and then save at the bottom. It only takes a second and says success in the window below the dropdown. Again diagnosis version 1122 is needed for this to work.

One word of warning. I had to reconfigure the APN to get network to work but I still couldnt receive MMS. So in the end I read that to get it set up you have to reset the phone and let the configuration steps set up network profile. I wasnt about to do that so I called AT&T and said I was going to another country and needed my unlock code to put a sim card in from there and they gave it to me. They said I needed another carrier SIM to input it. Instead I went to diagnosis and entered: #7465625*638*# That brought me to the Network Lock screen. I made sure disabled was checked and entered the unlock code they gave me on the phone in the NCK section and tapped execute. That unlocked my phone which let me use the samsung network profile tool available form the samsung marketplace (only on phone) to select the ATT (not AT&T) profile. Actually I toggled to AT&T then back to ATT and everything worked!