[Galaxy Note 3 Developer Discussion [Developers Onl] ruchirtrehan:
(Knox had been triggered on the the tested device already), This has been tested & working on Note 3 N900/Exynos on KitKat ND1 firmware which was on official status without root but Knox triggered, The file was flashed using Odin and after flashing I went into download mode and to my surprise Knox was been reset from 0x1 to 0 but the device status had turned custom (was official before flashing the Knox reset), however I will re-flash the firmware and see if Knox remains 0 and device status turns to official, also there are some different stuff in download mode which I hadn't ever seen before like EMMC PIN, Binary Sboot Version and all. I'll be attaching the screenshots for the same kindly find in attachments.

Edit/Update 1 : After re-flashing the firmware stuff like EMMC PIN and Binary Sboot Version has disappeared Current Binary has turned to official and the Knox has remained to 0 however System Status still appears to be Custom...

Edit/Update 2 : (Refers to previous updates regarding System Status being Custom and not turning to Official.) After trying to flash the firmware several times nothing really worked (nothing to do with Knox and Current Binary only referred to System Status being Custom) hence I went to stock recovery and wiped Data/Factory Reset and Cache Partition and then re-flashed the firmware (ND1 KitKat) and VOILA! Binary/System Status are now Official and now Knox is 0, seems a great success for the Exynos users, I also do have an snapdragon version so will be looking forward to it, screenshots attached....

Edit/Update 3 : The steps for resetting Knox (Exynos Note 3 ONLY!) :

1 - Download the bootloader.zip and extract bootloader from it (find in attachments)

2 - Open Odin and put device in download mode.

3 - Select AP/PDA (depending on Odin version you have) and select the bootloader (which was downloaded during step 1) don't select any other option in odin except F reset time and auto reboot (are selected by default).

4 - After the file is flashed go to download mode and check if the Knox has turned back to 0.

5 - Flash official firmware from sammobile and after flashing is done let the device reboot and boot up to device set-up screen, don't proceed the set-up for setting up device and turn of it off.

6 - Reboot to stock recovery (power + vol up + home) and wipe data/cache and flash the firmware again, once flashing the firmware is completed enter download mode and check if current binary and system status has turned to official if not follow steps number 5 and 6 again.

And that's pretty much it ;), you have successfully been able to reset Knox and regain warranty by this.

PS : I had done all this steps on ND1 firmware, and this will not keep root access, to root Knox has to be tripped or keep Knox 0 but Current Binary or System Status will be custom wit Knox being 0. Also to note this might get (patched) in future updates (bootloaders) if we look at Samsung's history of patching stuff :p, though not sure about it...

This will not work on any variant other than Exynos (Note 3) due to different processors and the boot system of both Exynos and Snapdragon. (the bootloader for (Exynos) contains Sboot which is only for the Exynos variant which cannot be used on Snapdragon as it uses Aboot). So this is by no way meant to work on SD variant or any other Samsung device ie S5/S4/Note 2 etc. and hence requested NOT TO USE IT on any other model than Exynos Note 3.

Edit/Update 4 : Downgrading Note 3 N900/N9000/Exynos from 4.4.2 to 4,3 has been successful, check out this post by me to be updated on steps regarding the same.

I'll be testing some work around's for the N9005 (Snapdragon) to reset Knox/Firmware Downgrade once I get that device as I have given mine to a friend, and have been saving money to buy a new or used N9005.