[Galaxy S 4 Q&A, Help & Troubleshooting] stephenphone:
Hi there,

I have the Samsung Galaxy S4 SPH-L720 Sprint (on RingPlus). I just installed Cyanogenmod on a Moto E and loved it, so figured I would install the S4 Sprint version on my S4. I have a feeling I didn't wipe the cache before doing so, because the S4 had a different recovery software (as opposed to TWPR which I was more familiar with). After rebooting I went through the whole "new phone" setup and it looked like the stock Android. So, like an idiot I decided to try installing TWRP so it would be more familiar to then install Cyanogenmod. I saw a few people recommend RASHR as the easiest way to install TWRP. So I used it and happily clicked ok when it asked if I would like to reboot into recovery.

It rebooted and hung with:

RECOVERY BOOTING.....
RECOVERY IS NOT SEANDROID ENFORCING
Set Warranty Bit: recovery

After rebooting again and again I got the same message. Then I read that flashing a stock ROM might do the trick. So I did the vol down, home, and power to get to the screen warning about damaging the OS, etc. Volume up selects the option to continue which does allow me to get to the "Downloading..." screen.

The upper left displays:

ODIIN MODE
PRODUCT NAME: SPH-L720
CURRENT BINARY: Custom
SYSTEM STATUS: Custom
KNOX KERNEL LOCK: 0x0
KNOX WARRANTY VOID: 0x1
CSB-CONFIG-LSB: 0x30
SECURE DOWNLOAD : ENABLE
WRITE PROTECTION: Enable
eMMC BURST MODE enabled

I plugged it in via USB (have tried several different USB cables and 2 different computers) it is recognized in Oden. But after selecting AP and choosing the ROM and clicking "Start" it hangs. I have tried a few ROMS now, which in retrospect was probably not wise, but I saw post after post saying, "just install a stock ROM". I've also tried installing TWRP and CWM via Odin and get the same hang. It hangs with Odin reading:

<OSM> Enter CS for MD5..
<OSM> Check MD5.. Do not unplug the cable..
<OSM> Please wait..
<OSM> L720_OD2_Pre-Rooted_Firmware.tar.md5 is valid.
<OSM> Checking MD5 finished Sucessfully..
<OSM> Leave CS..
<ID:0/004> Odin engine v(ID:3.1005)..
<ID:0/004> File analysis..
<ID:0/004> SetupConnection..
<ID:0/004> Initialzation..
<ID:0/004> Get PIT for mapping..
<ID:0/004> Firmware update start..
<ID:0/004> SingleDownload.
<ID:0/004> boot.img

And the phone reading "Downloading... Do not turn off target!!" with a tiny blue progress bar (maybe equivalent to 2%) that sits still indefinitely. The upper left on the phone adds the line:

START [224, 1440]

after the eMMc BURST MODE line. It is the same progress and same "START [224, 1440]" no matter what ROM or file I'm trying to add via Odin. I simply have to hold down the power key for several moments before it shuts down. I let it sit for 45 minutes with zero difference in progress.

What I didn't realize was that if I choose "cancel" (volume down) in the download confirmation screen it would reboot not in the recovery mode. I was thrilled to see the animated Samsung logo appear but after another 45 minutes of watching the logo continue animating with no boot progress I realized this wasn't going to get me anywhere.

I read that I can use Kies to do a recovery, but it requests a Serial Number, which is nowhere to be found on physical phone... Only the ESN and HEX numbers (and model number, etc.) Looking online everyone tells me to find it in my settings... which I can't access of course.

Since I can communicate via Odin, I still have hope... but it's running thin. What should I try? I'm using Window 10 64bit if that means anything.

Thank you for your help!

-Stephen