Knox still 0X0
1) Flash i9505_Downgrade_43_by_Leeno_.tar
2) Flash i9505_downgrade43_step2.tar
3) wipe data (if you don't wipe data s4 will hang at startup logo)
optional - root with .bat saferoot
After those steps, i9505 will have full working mkf version missing mkf bootloader.
Bootloader will not downgrade
if you want update to 4.4.2 or newer 4.3 than mkf and keep root and knox 0X0:
1) install mobile odin and open it
2) select option:
- "ever root" and
- "reboot in download mode"
3) select firmware and write. At the end it go in download mode, don't power on it
4) Flash only boot with odin from pc