Sprint Galaxy S IV SPH-L720 SIM Unlock Method
1. A Sprint GS4 requires baseband version MDC or MDL baseband. MF9 baseband will NOT work with this method. Downgrade baseband(modem) to MDC The File has been included. The first link will downgrade your baseband. You need a windows machine to get your device unlocked.
2.Open the phone app and enter dialer code ##3424# then select Qualcomm USB Setting and select the last option, DM + MDM + ADB and hit OK.You may be asked your for SPC/MSL code prior to the menu opening. You can get this from Sprint or by doing the following... Open ##3282# menu and hit Edit. Enter 123456 and it Ok.. you will be told it is incorrect. BUt that is completely fine.
NOTE: step 3 and 4 are only if you have Baseband Version ending with MF9
To check the baseband version go to setting and go to more (on the upper right hand corner) and select about device and see if your baseband version ends at MF9
3. Shut Down the Galaxy s 4 and make sure you have atleast 50% of battery remaining. press powerkey + Volume Down key + Home button until you get a warning sign for a android customization. Press Volume Up key to continue. You will enter the download mode in your Galaxy s 4.
4. http://www.mediafire.com/download/ow..._MDC_Modem.exe Download the file on your computer.
Open SPH-L720_MDC_Modem and extract file anywhere (ie desktop) and runSPH-L720_MDC_Modem.exe, Connect your phone in the download mode with your computer and upon port detection click start. This will downgrade your modem baseband to MDC.
5. Start Your phone now.
Download this as well
Install file Unlock_setup.exe and upon installation, open the application s4 flasher. Wait for a couple of seconds until you here the USB connection sounds. Then press scan and unlock. It should take a couple of seconds to unlock GSM on ur device.
7. Open the phone app and enter dialer code ##3424# then select Qualcomm USB Setting and select the MTP+ADB and hit OK.
Put any simcard in it and enjoy international GSM on ur device. This would also stop your invalid sim error on GS4 for domestic simcards.
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