yashsingh1/xdaforums huggingface dataset:
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
I will have it up tomorrow. Rooted busybox Knox removed and deodx
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] ACE3740:
Using Triangle Away or Wanam to say "Official"

Hi,

I have tried both Triangle Away and Wanam with Xposed Framework to reset and / or fake my custom flag back to "Official". Neither are working, Triangle away will reset it but as soon as I reboot it's back to the same "Custom" it won't stick. Does anyone have a solution to this? Or am I missing something. I am rooted and on Stock Rom, version NG5. This is not only for my OCD, but I have read that Miracast will not work unless it says "Official"

*** Please Help!!! ***

Thank You!
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Wanam worked on my stock nc6. Post 16 may give you some ideas.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] ACE3740:
Has anyone tried this on Stock NG5?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
https://mega.co.nz/#!MBkAAR6S!9RVyfy0Ac8rTcKb-IgF71NR1Zo1f44k_6q0Qf3Etg7U Here is the MK5 stock rooted busybox deodx init.d support zipalined deknox

And if any one needs mk5modem.bin

https://mega.co.nz/#!RF9ljTIb!ULaO8Gc2oz8tTNGpUeYqs0qeNjzU73JeBLcJg9m9ejs

Here is some stock tars I can upload the mk5 tar if anyone needs https://mega.co.nz/#F!0JdRkIZR!AqqKdbvba_Hpg5VrCmrbPw
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
Thank you, very much.

Just because I'm paranoid, does NOT mean they are NOT all out to get me.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Added to downloads section of OP. Credit bthorne79
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] keyro:
hi, how do i downgrade the modem to mk5? using you mk5 modem.bin with odin?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Its in the op but the bin file will go In the phone slot
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] keyro:
it fails on odin
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] VIIISecondRide:
Thanks

Many thanks to EVERYONE that has posted on here. I live in NE Colo and we have the armpit of cellular providers here-nothing else works and if it does Viaero charges them so much to roam they will willing terminate your contract early. The selection of devices, price, and poor service make it hard to have a nice phone.

I was able to root, down grade my modem, and unlock my l720t somehow with your excellent tutorials. It took me two days off and on but I got 'er running. So easy a ranch wife in the boonies can do it ;)

The only question I have left is, there is a 3g icon on top of my notifications that has a circle running around it. How do I toggle to 4g?

Thanks again!!

SPH-L720T

Android 4.4.2

Baseband Ver. L720TVPUAMK5

Build # KOT49H.L720TVPUBNG5

Used CF auto root
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] TheBeastJon:
After downgraded to mk5 from ng5 my sim card show it isn't inserted even though it actually is. Is downgrading the modem what actually caused this? I tried putting my phone in safe mode and my phone still says to insert sim. So I think it is a hardware error that just happened at the same time. What does anyone think?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] TheBeastJon:
Aww, I know what happened. My sim card had an adapter that was caught in the tray. I forced it out and it must of broken the tray. I just need to replace the tray. Thanks for the help though. I downgraded from ng5 to mk5 modem and it helped me unlock my phone. So thank you.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
OK I just tried to downgrade my modem from NG5 to MK5 for the first time fails in Odin looking for pit file I tried 3.07 and 3.09 two cables what have you guys been doing to downgrade and working. I dropped the modem.bin in the phone slot unchecked all boxes. I've never had a issue with Odin before has anyone tried with mobile Odin and did it work. I have only dropped my modem down to NC6 and went back to NG5 no issue. Can't seem to figure out why its not taking the MK5. I am on the NG5 firmware pushed with Odin not OTA I went through all the firmwares from MK5 to NG5 all with odin as I updated.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
[MENTION=4590326]bthorne79[/MENTION] did you try the modem.bin file posted by bradgrenz in the op? It Is the same modem file that cnexus originally posted and many ppls have used it successfully.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Yes his and mine both are from the stock tar
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Ok. Long shot but thought maybe something happened when your pc pulled out and saved the file. Kinda of like a corrupted download. Who knows why they happen. They are rare but sometimes just happen.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Im going try to do it while on stock was trying it on aosp but that should not matter or go down in steps ng5 to nc6 to mk5
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Cool let us know what happens.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] VIIISecondRide:
Voicemail?

Okay, the l720T is doing good, just would like to know where to toggle 3g/4g AND I just realized I can't dial MY voicemail. There doesn't seem to be a setting to reset the voicemail dial-up number. Do I just need to set a speed dial for it?

Thanks again!!
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] daniel4653:
On stick there really isn't any way to toggle between 3g and LTE.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
I just upgraded my google nexus tablet to lollipop. Wow! Lollipop is very different in terms of layout. It will be interesting to see what else is under the hood. Im getting a glimpse of what will likely come to our 720Ts. If I see anything eye catching, I'll post.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] mrtech12:
Did you find out how to turn 4g or LTE on ?

i have unlocked my l720t and it works only on 3G. do you have any update how to turn 4G or LTE on.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Are you sure the carrier you switched to supports 4g in your area?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] VIIISecondRide:
MRTECH12 I have not. I do know that we definately have 4g coverage as it is the big selling point for Viaero!

EASYRIDER77 said he toggled 3g and 4g but I didn't find out how. I will keep working on it and keep you posted.

I also cannot seem to recieve MMS messages and I have checked my APN settings several times. Must be some other setting.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] mrtech12:
[MENTION=5662793]bgmg[/MENTION]: yes i do i have 4g and LTE service because i am using same SIM on samsung galaxy s3.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Is your 720T stock? What version is it? What modem are you running?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] mrtech12:
SPH-L720T

Android 4.4.2

Baseband Ver. L720TVPUBNG5

Build # KOT49H.L720TVPUBNG5

Software ver. L720TVPUBNG5
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Is it deoxed?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] mrtech12:
how do i find that out?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
That response pretty much tells me you are not using a stock deoxd. But to answer your last question, have you ever flashed anything using odin or a custom recovery on to your phone?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Osirus71:
Have you not tried this Lollipop rom?? Using it on my girlfriends L720T and works great...

http://xdaforums.com/galaxy-s4-sprint/development/rom-5-0google-play-edition-lrx219-12-24-t2982384
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] mrtech12:
i just rooted using odin super user(CF-Auto Root) and i didnt flash anything.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
No, I want to stay stock as long as my phone is doing everything I want it to do, and thank you for the post. It was a good read?.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
In that case, I'm out of ideas. I hope someone who has more experience in unlocking will assist you.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] VIIISecondRide:
Easyrider77 how do you toggle between 3g and 4g?Is there any way to change the number voicemail dials to retrieve it? Is there anything besides MMS APN that I need to edit so I can recieve (download) MMS pictures in messages? Anything will help Thank you
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] VIIISecondRide:
UPDATE_ So I found out today, I can download MMS images while on WiFi, but not on data...
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] afbergel:
Hi guys, me again.

My L720T is still hard bricked.

I need you guys to help me out by creating a debrick image for this model.

It's very simple and will only take 5 minutes of your time.

First flash attached zip file using recovery

This zip will create a 200mb debrick.img file inside /sdcard

After that just copy debrick.img to computer zip and upload it somewhere.

zipped file will be around 30 to 40mb.

Thanks!
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
I took a quick look at the first couple of posts and that is the first ROM I've seen that's attempted to reawaken my Obsessive-ROM Updating Disorder again... :eek:

Doe it have WiFi calling? That's a must-have feature for me and I couldn't find a mention of it in the thread... #blamesprint

Would love to know how to port that feature.

TIA

-Jerry

http://www.xda-developers.com/do-you-have-obsessive-rom-updating-disorder-ord/
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
OK, tried the ROM and like it very much, but not yet a DD for me. Restored from nandroid, and something is wrong with acess to the /data partition. It seems like apps without root cannot write to areas in /data/*. I reformatted (not wiped) /data and restored again, but that didn't help, nor did fixing permissions in TWRP. Any ideas?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
Fixed it by flashing a TW ROM, wiping that and then restoring again...Voila! :cool: :good:
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Does anyone know how to backup the baseband on this phone? I recently got a brand new 720T but my baseband ends in MI8, and nobody else seems to have that. It doesn't really bother me all that much but I recently rooted and installed a custom recovery and flashed the Google Play Edition ROM (5.01) and i don't get LTE at all, which I believe is because of my different baseband. Any ideas?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
Are you sure it's a 720T, is that what it says on the sticker under the battery? Because from what I find on Google on the MI8 or XXUEMI8 is that it's from the GT-I9505, the S4 International model.

And sorry, but I don't know how to extract the baseband, only ways I know are finding one on XDA here, or downloading the stock tar from sammobile, and extracting the modem from that.

They have the XXUEMI8 modem/baseband here, http://xdaforums.com/showthread.php?t=2192025

Edit: Also sammobile doesn't show the XXUEMI8 on the I9505, but if you Google XXUEMI8, you find out that it was a leaked Android 4.3 JB firmware for the I9505.

About the LTE, have you tried going into settings and I think mobile data or mobile networks and switching your preferred network type.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] molitar:
How can I downgrade modem to MK5? The file is a bin so only usable in Recovery but it keeps failing. I tried to locate an md5 so I could use Odin but I can not find an md5 for MK5 anywhere. This is the last stop preventing me from unlocking for Domestic.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Weird, when I got my phone it was on 4.3 and had absolutely no updates, which i thought was weird since the GS4 has had 4.4 for a while now. Also i'm 100% sure I have a 720T. Besides the marking under the battery, there are several other places on the phone that have the imprint L720T, plus the full baseband is L720TVPUAMI8, and I ran CPU-Z and made sure I have the Snapdragon 600. Oh and the LTE did work fine on the stock rom, but seeing the lollipop ROM I just couldn't resist flashing it.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
You Odin the bin file.

Happiness is a warm Fuzzy.

---------- Post added at 01:18 AM ---------- Previous post was at 12:54 AM ----------

That is weird, but by your full number that's definetly a 720T modem. If your talking about danvdh's GPE 5.0.1 ROM, I use that a lot. Sometimes when I reboot I see LTE, but then it drops to CDMA, I think that is because I'm on Ting and have mobile data turned off on their website. Sorry I can't help more.

Happiness is a warm Fuzzy.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Do you have a Sprint L720T or perhaps a better way to ask is who is your carrier?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] japush:
Need for a copy of the /carrier folder from working Sprint L720T

Hi there friends, could anyone post their zipped Device/carrier folder from s working Sprint L720t? I'm stuck in HFA loop every time I restart the phone or want to Renew Profile. Most likely it's the corrupt /carrier files. Thanks in advance!
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Well thanks anyways, I appreciate your time and help. Oh btw, you said Odin the BIN file, is that a method of backing up the baseband? If it is, could you elaborate? I'm pretty familiar with rooting and etc, but am still getting use to Odin and all since this is my first Samsung phone.

Yup, my carrier is Sprint, and I have the Sprint L720T phone since the letters "SPR" is near the battery.

Edit: despite my different baseband, I flashed the stock rooted NG2 ROM by MXMR, and suprisingly LTE worked. Not sure what the problem is but the lollipop GPE ROM will not let me use LTE at all.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
Sorry, You Odin the bin file was [MENTION=1628339]molitar[/MENTION]

I was on tapatalk and it added my post together.

---------- Post added 24th January 2015 at 12:03 AM ---------- Previous post was 23rd January 2015 at 11:54 PM ----------

If it's danvdh's GPE ROM check out this thread http://xdaforums.com/showthread.php?t=2557353

It is the same exact file as his Sprint ROM, but there are over 15,000 posts, so you might find your answer there.

From what I've seen, they will say update your modem.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Yea, that is what I am debating right now. But flashing the modem without having a backup of my current/stock MI8 is a little nerve racking. Well anyways nothing much more I can do for now. I'll just wait and see. Thanks anyways for your help fuzzy, I appreciate it.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
I would think that to make a backup of your stock modem, you would have to use adb.

I think its on the /firmware-mdm partition.

But I have no idea what the commands would be.

Something to look into, anyway.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Send a message [MENTION=4590326]bthorne79[/MENTION]

I'm pretty sure he knows how to backup a modem. If he has time, maybe he can help. If you find out and you don't mind, please send me a pm with the details. I'd like to have it in my pocket.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
I tried looking using root browser but there was nothing there..

I believe i sent a message to him, but i checked my sent box and it didn't show anything there (i've been a member for sometime but i'm not too familiar with xda). I will just have to wait and see if he responds or not. Thanks for the help btw.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Your welcome. Good luck.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Honestly I don't know

That firmware is new to me And its not on sammoblie did you just get it.

But this might help out http://xdaforums.com/showthread.php?t=2450045
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Yea, I was thinking I might have gotten an experimental test one. But it came with 4.3 which is old, so i'm completely lost. My only issue It is that LTE won't work on the 5.01 GPE ROM but a lot of people are saying the same so It might not be the baseband. I"ll try to use that link to see if I can make a backup, Thanks for your help, appreciate it.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Gpe is a weird one cause it actual came from international s4 and ported over CM base
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Hmmm, then i guess i'll try Nivron's 5.02 CM12 for jfltespr and see if LTE works. Thanks for the info.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
The team I'm on (OctOS) should be releasing something real soon again just getting some mods added.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Setow:
Can't wait :)
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] phantomlord87:
Hi guys I recently unlock my sph-l720t with SSU method on stock 4.4.2 firmware and mk5 modem downgrade and I'm using a straight talk AT&T sim. I did the correct apn setting but I'm not getting "4G" Internet speed it just still on 3G. if is not much to ask, can someone guide me on how to release or configure my phone to make 4G or LTD happen? Thanks in advance.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Romboter:
Why does the OP link to odindownload.com? This is a known bad site that serves malware and a virus.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] ROMANTiC KiD:
I thanked you by accident. But you will never get 4G or lte speeds because of different bands. 3g is the only Internet speed you will get.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
To my knowledge, that is the official odin download website, and my security antiviral apps are not alarmed by visits to this website. Do you know of another official site?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] patonovich:
link down

hi the link is down of the modem
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
I just checked all the modem links in the downloads section of the op. They all tested good. Can you be more specific please?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] liquidrea1ity:
Is there a stock recovery file available for 720T on ng5, or is it common to single band 720?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Romboter:
If it is the official site it's compromised. Sorry I don't have legit links to share, but did want to warn.

Example, odin 3.10

The link on the site is, get.file20desktop.com/DownloadManager/Get?p=2329&d=25076&l=24264&n=1&filename=Odin%20v3.10

It redirects to get.ground0102.info/1422505346/get6?p=2329&d=25076&l=24264&n=1&filename=Odin+v3.10

Which downloads a 500kb file which pretends to be odin but actually installs at least 4 malware and a virus.

Removal guide, malwaretips.com/blogs/zoomifyapp-removal/

Yes, I actually had to go though all the steps, it was that invasive!

Odin 3.1 is actually a 900kb file when downloaded not 500kb
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] patonovich:
oh yes sorry, the modem mk5 for unlock galaxy s4 sph-l720t
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
I just used the link. I was able to download the mk5 modem with no problem. It might be your Browser. I used Chrome on my android.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
When I installed odin from this site long ago. I had no problems.

Where did you get your valid 900k file from?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] liquid_arts:
Is there a tether fix for NG5 yet?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
please read the op (post 1)
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
What is the folder/location that the OTA updates are downloaded to? Search is not being my friend...

TIA,

-Jerry
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] fuzzybuffalo:
/cache
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Osirus71:
A fix for what???
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] liquid_arts:
WiFi tether, I found the tether router app through google since sprint locked it out from the play store. I got it to work for my tablet, but it I can connect my laptop to the tether but still no internet.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] vinman07a:
How should I go about unlocking this phone?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Read the unlock section of the op (post 1)
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Has anyone every tried this https://play.google.com/store/apps/details?id=net.snclab.RootKeepSurvival

Supposedly you can back up your root, upgrade your phone OTA to the latest update, and then restore root from backup. This is made by the same person that made wifi tether router (fabio grasso)
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
I guess we won't be getting any more updates to wifi tether router. Where did you download it from? Please post link.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] liquid_arts:
Here is where u got it from.

http://globalapk.com/android-apps/9602-wifi-tether-router-v604.html
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bgmg:
Thanks. Interesting he is not charging new commers for the app on this site. Makes me wonder if this site is legit, safe, and free of malware. None the less, thanks for the post.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] liquid_arts:
I hear you there. I was wondering the same thing after I dl'd it.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] patonovich:
yes tk you, finally i unlock my phone
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] bthorne79:
Odin 3.09 https://copy.com/pA2rdk42lBJDANkz
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] shadowcliffs:
After unlocked with MK5 modem, does it has to stay at MK5?
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
Thanks. Will check there after I restore that particular nandroid... :good:
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] conflikt:
Is there a stock ng5 kernel? Lost my wifi after installing the stock ng5 rooted zip. Thanks.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] JerryGNYC:
IIRC, that ROM has the stock kernel (that's why it's called stock). Are you running the NG5 modem? A mismatch between kernel drivers and modem firmware could possibly cause something like that (IMHO).
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Cooljb:
720T Update

Looks like we've got an update coming. OA3 posted on Samsung open source site.

http://opensource.samsung.com/reception/receptionSub.do?method=sub&sub=F&searchValue=sph-l720t
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Cooljb:
Hot off the presses from sprint:

http://support.sprint.com/support/article/Find_and_update_the_software_version_on_your_Samsung_Galaxy_S_4/WRNServiceAdvisory_542_GKB65037?INTNAV=SU:DP:eek:V:UG:SamsungGalaxyS4:FindAndUpdateTheSoftwareVersionOnYourSamsungGalaxy

I was hoping it might be 4.4.4, but it just says WiFi calling enhancements.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Dngrsone:
Link is broken... try turning off smiles for this post.

maybe this will work
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Cooljb:
Done. It was working for me before turning off smiles though... Strange.
[Sprint Samsung Galaxy S 4 Q&A, Help & Troubleshoot] Dngrsone:
Might be because I'm on my phone... I don't need WiFi calling. It seems kind of counterintuitive, actually-- I have a freaking cell phone, why do I need WiFi to make a damn phone call?

... unless this is Sprint's way of saying they aren't going to upgrade the networks anymore.