Why is flashing my stock ROM using Odin failing?

[duskbdawg]

I'm kinda new here and I wanted to see if this would help. I have a Samsung Galaxy S4 Sprint and it is rooted and running Cyanogenmod 12.1. I used Odin to root it in the first place but now it started becoming really slow. I reset the phone, but kept the root and CM ROM. After doing that my phone worked a lot quicker but my data stopped working and sometimes I won't receive texts. I've been looking around for a solution for it everywhere but I haven't found one so I decided to flash the stock ROM to return it to complete factory settings which I hope fixes the problem. I downloaded the stock firmware for my phone and tried flashing it in Odin but everytime I do it it works for a second and then fails. Please help

 

[josearmz10789]

make sure you are using the same android version you are in right now. For example flash 4.4.2 if you have it on your phone and not a previous version.

 

[ExNihilo01]

make sure you are using the same android version you are in right now. For example flash 4.4.2 if you have it on your phone and not a previous version.

CM12.1 is Android 5.1.1, but there is no 5.1.1 stock firmware for the Sprint GS4, as the last official update we got was 5.0.1, so if there was a 5.1.1 for GS4 it wouldn't be stock, right?

Personally, I'm completely satisfied with CM12.1 on my Sprint GS4, but I'm still curious about OP's situation.