Root G900AUCU2AND3 Samsung Galaxy S5 (G900A)

If you already installed the OTA update G900AUCU2AND3 Samsung Galaxy S5 SM-G900A and now wants to retain root, this will cover how to root it correctly.  As I seen some few people have had ended-up into soft-bricking their phone while installing root, so I decided to put this up as a  word of advise to keep your phone safe in-case you are about to root your phone.

As you may know, the G900AUCU2AND3 OTA update includes some patches, to the recent root app found by Geohot and that so-called Towelroot.  The "Towelroot" was is indeed worked on previous  G900AUCU1ANCE 4.4.2 stock firmware, but it is not covered anymore due to the Towel root's capability and limitation.  This limitation was already addressed by the developer himself that it can only support phones with software build version not exceeding on June 3 2014.  So every phones that already received the OTA update right after June 3, 2014 the root exploit will no longer work, as simple as that to consider.

So if I already updated to G900AUCU2AND3 OTA update, how can I root then?
No you can't root the G900AUCU2AND3 update as there is no , but as the root app clearly emphasized that it will worked on on updates before June 3, 2014 and was already proven to work with the old G900AUCU1ANCE, so  all you need is revert back your phone to the old 4.4.2 G900AUCU1ANCE Stock Firmware from the current 4.4.2 G900AUCU2AND3 OTA update on your Samsung Galaxy S5 SM-G900A. It may sound sound too easy but it also take a lot of work to do so just to regain root.

Again this is only a guide and I am not encouraging you to do so, I'm just pointing you the right direction to keep your device safe. But if you badly needs root just read this guide here thoroughly and grab the full stock firmware G900AUCU1ANCE. Once you carefully revert back your phone to NCE stock firmware, try to root again using towelroot. Just let me know if you have something to ask.

Source: XDA-developers