Originally Posted by Frankenscript
I'm thinking of buying an M919, carrier unlocked, to use on ATT, so that I can get a proper recovery and have full access to custom ROMs without the safestrap limitations.
Is it safe to say that:
1. If I buy a T-Mobile S4, and it comes carrier unlocked, it will work fine on the ATT network, including 4G / LTE? Lots of data points suggest this but I haven't heard it explicitly stated...
2. Though I could use the phone as identified as an M919, I really want Play Store to see it as an I337 (ATT version), so I can install some ATT specific apps. Is there any problem flashing a build.prop (available in the ATT threads) with the ATT identifiers & APN info, to enable this?
3. Are there any gotchas I should be aware of? Basically, I just want a phone with unlocked bootloader / kernel so I can play. Not too worried about Knox/warranty.
Any insights would be appreciated!
Will the T-Mobile S4 work on the AT&T network; yes it will work if it's carrier unlocked. I purchased my M919 full price out of contract while I was still on AT&T service. Once I carrier-unlocked I was able to pick up AT&T's 4G/LTE and was even able to make use of the AT&T 3G Microcell device which transmits a 3G cell signal and runs over your WiFi. I now have Net10 Wireless with an AT&T SIM card and I still get 4G/LTE when it's around.
Your second question: I do believe that's all that would be required. I'm not 100% sure if just modifying the build.prop would allow you to use the AT&T-specific apps in the Play Store. I never used them to begin with so I never explored whether or not I could make them work on the T-Mobile firmware. Now, I know this involves more than just a build.prop edit, but a 100% sure way to get AT&T Apps working would be to flash a custom ROM based on AT&T firmware. Being that you have a T-Mobile device and are using it on another carrier's network, always remember; when it comes to Odin especially, flash things meant for the T-Mobile M919 ONLY. It doesn't matter that you use AT&T service, your device needs T-Mobile Modems/stock firmwares/etc.
As far as gotchas... not that I can think of. The M919 has an unlocked bootloader and even with KNOX is very easy to root and use custom ROMS on. If you're not concerned with KNOX then you really don't have to take into consideration any special rooting method, no safestrap junk, etc. Without root, just flash a recovery in Odin and flash away.