Posted on Leave a comment

Fix No Sound/Calls on Sprint S4 – SPH-L720

After flashing many custom ROM’s that work, you may run into a no sound or calls problem after a normal flashing procedure (data wipe –> ROM/Gapps Flash). If this problem happens to you, you most likely have run into a baseband (radio), kernel, or bootloader incompatibility.

Recently, I ran into this issue again after flashing my Sprint S4 (non-Spark) with a Lollipop 5.1.1 ROM (Exodus). From my reading, I’ve usually found that this happens when the modem or kernel isn’t compatible. I’ve always read that you should upgrade your modems in order to prevent this: MDC > MDL > MF9 > MJA > MK2 > NAE > NG2 > OD2 > OH1.

I was starting from the MF9 modem (also MF9 bootloader to prevent tripping Knox). Sound was working all the way up to NG2. When I flashed OD2, that’s when the sounds stopped working. I tried downgrading in the same order, all the way back to MF9. However, the sound was broken even when I flashed back my original Optimized CM12 ROM. No matter what ROM/modem combination I tried, I couldn’t get sound working.


  • No system sounds – ringtones and dialer made no sounds.
  • No music – no sounds whatsoever could be produced
  • Calls – would lag seriously on dial and answer. The other person could not hear me and I couldn’t hear them.


What I figured out from other XDA posts was that I needed to flash everything back to stock. I had a hard time finding the MF9 stock rooted ROM for the Samsung Galaxy SPH-L720 that would do a complete restore so that my bootloader wouldn’t be changed. My warranty has far run out, but I wanted to stay on the MF9 bootloader so Knox wouldn’t be tripped. Credit to the steps below goes to user crawrj from his XDA post and Beezer80 from his XDA post. The steps below assumes using a Windows computer with ODIN, so if you are a Mac user like me, I suggest finding a Windows computer so you can do this easily.

  1. 3 Assumptions: you have a custom recovery installed on your phone (like TWRP), Windows computer, Samsung drivers installed
  2. Download:
  3. Turn your phone off. Turn on by pressing Power Button + Volume Down. You should get to download mode on the S4
  4. Unzip and open the Odin 3.07 folder. Edit “Odin3.ini”. Change “PhoneBootUpdate=0k” to “PhoneBootUpdate=1”. Save.
  5. Start Odin 3.07.  Click the “Bootloader” button and choose the “mf9fullupgrade.tar.md5” file you unzipped. Then click Start.
  6. Turn your phone off. Turn on by pressing Power Button + Volume Up. You should now enter your custom recovery. Do a Full Wipe. Then install “”. Then install “”.
  7. Restart. You should now have a Stock Rooted Sprint S4 on MF9.

What’s Next

Now that you have restored your phone back to MF9, you should now be able to place calls and listen to sounds like normal. If you plan on flashing another ROM, I recommend the JDCTeam’s 5.1.1 CM 12.1 Optimized (based on Android 5.1.1, Lollipop). I installed using their directions and am using the MF9 baseband and bootloader. I’m now using it as my daily driver. The battery life is fantastic and there is no lag. On all other 5.1.1 ROM’s I tried (even after fixing my sound as described above), seemed to start lagging heavily on all apps randomly towards the end of the day.

Leave a Reply

Your email address will not be published. Required fields are marked *