[Verizon Samsung Galaxy S 4] docnok63:
I'm currently running this with Synergy r104. As previously said, it works 90% of the time if you follow the directions in the OP. The dev is Chinese and sometimes doesn't fully explain things, so I wrote up the instructions in detail for the DNA board. This helped a lot of DNA users get it going, so...:

Here is my quick guide to installing both FX and XHiFi. You don't have to install both, but I recommend you do for maximum customization:

1) Obviously, download the files and extract both 4.x .apks (the bottom ones.) Make sure your BusyBox is the most current version.

2) Uninstall any other sound mod or DSPs (you can leave HDSoundEngine2 if you have it installed. They are compatible). This includes DSPManager, Noozoxoide, and Nexus Louder. DO NOT delete MusicFX if that is installed on your ROM. You'll need it later. To delete DSPManager, use a file manager with root privileges and go to system\app and delete the .apk.

3) Use this same file manager to put the .apk's in system\app. Do NOT open them. Just put them there and reboot into recovery. Wipe dalvik cache and cache and fix permissions.

4) Open each Viper app. Give them root permission and then wait for it to say it needs to update. For FX, install the CortexA8 with NEON driver. For XHiFi, choose the Ax with NEON. DO NOT do anything else in the mod except install the driver. Reboot into recovery and dc\c wipe, fix permissions (I know you just did it. Do it again. Boot into Android.)

5) Once back in Android, go immediately into Settings\Sound. If you have a section called Music Effects, click it and choose FX and select ALWAYS if you have the option.

6) Plug in your headphones and start a music app. Fire up FX. This time, if FX says it needs to update, you've done the installation wrong. Review the steps above and try again. Hit the top box to enable the mod and then use menu to check your driver status.. Everything should say YES. Don't mess with it just yet...

7) Go into XHiFi and enable the mod. Again, check the driver status and make sure everything says YES again.

8) Now tweak them as much as you want. Set them to however your ears like them. Don't forget to extract IRS samples into sdcard\Viper4Android\Kernel folder (if they don't exist, create the folders), turn on the Convolver in FX, and choose your favorite (http://www.mediafire.com/download/9am1sogfq9lm31d/en_IRSamples_331+IR.zip).

9) If you've followed all the above to the letter and it still doesn't work, try switching to compatibility mode. If that doesn't work, try switching to safe mode (no dc/c wipe and permissions fix needed.)

10) If none of this works...go into system\build.prop and ensure that the line reads:

lpa.decode=false

If it says true, use a text editor and change it. Most of the time it will say false, but your ROM creator or a mod/app may have changed it.

A couple people here have reported that if you check your driver status and it says it's disabled, you can use the menu button and select 'Switch to Safe Mode', immediately switch it back to Normal Mode and then reboot.

11) If you've done all the above, either you've installed it wrong or it simply won't work with your ROM.

*** Special media player tip: If you use PowerAmp, you have to turn off Direct Volume Control in PowerAmp setttings\Audio\Advanced Tweaks in order for it to sound correct.***

The most common error in installation is people just clicking the .apk to install. This installs the app to data\app instead of system\app. You'll get the warning message that the driver needs to update every time you start the app and when you check the driver status it will say NO for Enabled and Processing (it's not modifying your sound at all.)

I hope this helps some of you, because this is a pure eargasm once you install it right.

Enjoy!!!

Doc