my ? is why would you want to attempt to flash a custom rom without having a custom recovery? safestrap I have just recently found and have been bound to moto devices and used on them and recently got a s4... still using twrp for the time being because it looks like you can only use touchwiz roms on it. recently found a carbon rom that is amazing for battery life but still probably will flash for safestrap this week.
I am pretty sure I have stock flash file will let you know that when i falshed stock via odin it would not install new update.