Already rooted ATT Samsung Galaxy S4 and TWRP installed how to get MF3 update
If you are like me, one of the first things I wanted to do with my brand new Samsung Galaxy S4 was get it rooted so I could do all kinds of cool stuff that you just can’t do without root access. So, the method that I used which was unbelievably easy was the Casual root method with a one-click interface which the XDA thread can be found here:
ATT recently as of mid July started pushing out a new firmware update which has many performance benefits compared to the older stock firmware as well as the ability to install apps on the external SD card which are great benefits to accepting the new update. Up until just a few days ago, root access to this new firmware was not able to be achieved. However, no matter how good security updates are, the good and brilliant guys over at XDA were able to crack root access to the new MF3 update. Keep in mind at this time though, custom recoveries have not been able to be installed. The root access is just that – only root access. So there is no way to get back to the stock MF3 unrooted state at this point just yet or return to it if something goes horribly wrong.
If you decide to accept the MF3 update and want to run the OTA update, an issue that you will run into with a custom recovery such as TWRP and trying to get to the I337UCUAMF3 firmware version is that you can’t run the ATT OTA in TWRP and I am assuming in CWM. You will need to flash back to the stock ATT ROM with the stock recovery image to be able to use the MF3 update. How do you do this? There is another really great thread on the step by step process you can go through to get back to the stock ATT I337 ROM. Check out the XDA thread here:
Re-Rooting your MF3 updated phone
After you have flashed the stock ATT ROM back to your SGS4 and you have updated to the MF3 firmware version, you can give the new root method a whirl by checking out the XDA thread on the new root method for the MF3 update here: