Unroot Galaxy S4 topic

Hi I am very new to this rooting thing, im trying to unroot my galaxy s4 AT&T. I have used oden and the stock firmware I337UCUAMDL_I337ATTAMDL_I337UCUAMDL_HOME.tar I get an fail right when odin starts it says this
<ID:0/005> Added!!
<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> I337UCUAMDL_I337ATTAMDL_I337UCUAMDL_HOME.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/005> Odin v.3 engine (ID:5)..
<ID:0/005> File analysis..
<ID:0/005> SetupConnection..
<ID:0/005> Initialzation..
<ID:0/005> Get PIT for mapping..
<ID:0/005> Firmware update start..
<ID:0/005> aboot.mbn
<ID:0/005> NAND Write Start!!
<ID:0/005>
<ID:0/005> Complete(Write) operation failed.
<OSM> All threads completed. (succeed 0 / failed 1)

is this the wrong firmware? im sorry for such a boot questions but I have no idea what to do. Thank you for all your help. I am on android 4.3