I recently traveled to Europe with my Sprint Galaxy S4 world phone. I planned on getting a pre-paid GSM SIM card to use for Google maps and navigation. It turned out great.
At the airport, I found a “SIM Local” prepaid wireless shop and paid 20 euro (about $26 USD) for a Meteor SIM card that included 10 euro for 1GB data and 10 euro for calling (it costs 15 cents euro to call international, about 60 minutes). That will be plenty for just a week’s travel.
Before I arrived, I rooted and manually unlocked (following this guide) the stock TouchWiz ROM on my S4. When we pulled the Sprint GSM card and put the Meteor card in, voice and texting worked right away; however, the data didn’t work and no Edge, 3G, or HSPC (H+) symbols were displaying. I had missed one last step that no one had mentioned in the root and unlocking demos: APN unlock. In order for the Sprint S4 to work on GSM data, you must unlock the APN settings that Sprint hides and locks by default.
After the APN settings are unlocked you can now program your phone to use the GSM data plan. I have been experiencing amazing data speeds after setting it up.
Here’s how to finish unlocking your Sprint S4 APN settings:
1. Download ES File Explorer from the Play Store
2. Open ES File Explorer and open the settings by pressing the key next to the home button
3. Scroll down to Root Explorer and turn it on
4. Tap the word Root Explorer And choose Mount R/W.
5. Switch all the buttons to the R/W column and click OK
6. Go to your / folder and then the System folder
7. Open Build.prop with the ES notepad
8. Click the button in the top-right and choose edit
9. Scroll all the way to the bottom and add these two lines:
10. Click the back button and save
11. Restart your phone
12. Download Offline SIM APN Database from the Play Store
13. Open Offline SIM APN Database and click Search APN Settings for this Network. Choose the carrier.
14. Copy the settings and paste them into the Go to Android APN Settings screen. You’ll need to click the button left of your home button to add a new APN
Done! Data should now work.