Credit for this discovery is not mine alone. It has been tossed around for quite some time that a version of the Japanese radio may hold the key to unlocking USA capability. XDA members Noncs and Lightsword1942 should be recognized for finding the proper Japanese radio. Please be sure to express your gratitude and encourage more work on this unlock by thanking folks involved and when possible donating. This keeps the cup filled and keeps the work going.
So you want to unlock your Photon to use on AT&T, T-Mobile or some other USA GSM/UMTS carrier. Well this is how to do it. The poll I have here is important. PLEASE DONT TAKE IT UNTIL IF AND WHEN YOU TRY TO GO BACK TO STOCK SPRINT OR RETURN TO SOME OTHER CDMA CARRIER! Most of the answers to "CDMA is still not fixed" have been folks that appear to be not very active in the community, or have found this googling how to unlock GSM for the photon. I have decided that it comes down to NOT following the instructions correctly/not understanding what currently is needed to get flash the GSM radio AND/OR get back to CDMA.
1-RSD an .sbf to stock base.
2-Unlock your bootloader.
3-Root your phone.
4-Install a recent custom recovery.
5-Perform a nandroid backup.
6-Restore a nandroid backup.
7-Flash a .zip from a custom recovery.
8-Create, edit or flash APN's. (for data)
9-Boot into recovery, fastboot, etc.
8-Accept responsibility if you screw up.
If you don't know what any of this is or means, than leave this thread and don't come back until you do and are comfortable with them. A good place to start is LokifishMar's All Things MoPho! Thank him and fill his cup! Please leave questions about these things at the proper threads.
Things YOU need to know:
1- The radio file for unlocking GSM/UMTS will be referenced KDDI for purposes of this thread. KDDI=GSM RADIO
2- Flashing KDDI will enable USA GSM/UMTS and allow USA carrier sims to work on your Photon.
3-Currently the KDDI results in error when flashing to Electrify. Sorry USCC guys, hopefully it gets worked out soon.
4-Flashing KDDI will break Sprint service while you are using it. This is not permanent and CAN be regained.
5-The GSM/UMTS functionality needs rom support! The rom devs are working hard to integrate into ICS based roms. Stock sprint works on GSM, although occasionally GSM would break after some time during testing. Currently the best functional rom for GSM is peetr's custom 2.3.5 hybrid and is currently the recommended ROM. Please don't gum this thread up with data and other issues after using the KDDI. It works and any issues with service are NOT here. Go to the ROM thread you are using.
1-SBF to stock base. Root your phone, unlock bootloader, install custom recovery and perform a nandroid backup of your stock rom!
2-Flash KDDI radio from recovery.
3-Flash your ROM. You may need to enable GSM/UMTS in your mobile network settings. You also may need to enable data roaming and set your APN's.
4-Profit! If all you wanted was the unlock then your done! otherwise...
Get Sprint stock back:
5-Restore your nandroid backup you created previously.
6-RSD the stock sbf.
7-Reboot and reactive Sprint (Hand's Free)
You can also if you choose flash a stock sprint radio and manually program to Sprint or another CDMA carrier instead of flashing back to stock.
Follow the instruction here after flashing a Sprint stock radio. Substitute the data flashed for Cricket with the data from needed from Sprint or your CDMA carrier. http://www.cricketusers.com/sprint-m...ernet-mms.html
WARNING: This is not the easy way, the first method is recommended. You can easily bork your phone messing around with the software at the above link.