update straighttalk galaxy s4 OS?

By no means a droid noob, but not at all knowledgeable about this possibility, so you may have to spell things out for me in basic terms. -laugh-

I'm runnng a Galaxy S4 (SM-S975L) from straighttalk. OS is 4.3. My understanding is the OS is currently maxed out on the phone as purchased, & that to upgrade to newer OS I need to root, losing ability to OTA upgrade & requiring manual updates from that point on. (Phone supposedly also locked & not unlockable, or at least so says straighttalk.)

A number of my old apps (on a previous phone using kitkat) are incompatible, & I just lost access to some I've been using on this one that now apparently require higher than jelly bean. So, question:

Can I safely (read, reliably *&* safely!) root & then manually upgrade to at least 5.x (if not higher), & if so how do I go about it? I've read enough to know there are at least some solid root apps out there, but also enough to know if I do it I need to go verrrrry carefully, & even then "ainno guarantees"! Any & all info/aid/assistance/guidance/etc., MOST greatly appreciated!!


Android Enthusiast
The answer is no, I am sorry. I have researched this subject for a friend who has what you have a StrtTalk. So your right the bootloader is locked on those ST phones. So this means you can not root it the conventional way with Odin.
My understanding is the only way to root these is either use Rommanager to flash superSU or chance using Towelroot.apk.
Then if you luck up with that then copy a TWRP Custom Recovery is a breeze with this.
dd if=/sdcard/twrp.img of=/dev/block/mmcblk0p21


Thread starter
Thanks much to both of you! I had the feeling that might be the answer, so not *totally* disappointed. Info much appreciated & assimilated. jfalls, I'll make sure to checkout that thread when I get a sec later today. Sonic, good & straightforward -- I like that; definitely my own approach. THANKS!!



Android Enthusiast
I don't use Custom roms anymore, they are a pain IMO. If you can get it to flash twrp and create the backup of the original rom is a big plus. I prefer the stock rom rooted. Much more stable.