Samsung Galaxy S3 LTE and VOIP Microphone Issue

I heard about FreedomPOP from my brother, basically you get 200 minutes, 500 Texts and 500MB data free each month. They use the Sprint network and support 3G & LTE. The way it works is everything goes over the data connection. Calls are routed over VOIP and texts are about the same. This actually works really good for me as I get basically no service at home on Verizon or Sprint, but I have good WiFi. It will route over any available internet connection, so you could even use it overseas (on WiFi). There are some issues I can't resolve ATM. Here's What I've run into so far:

I'm running a SlimKAT 7.0 on a Samsung Galaxy S3 (Sprint), so these may or may not work for you. I TAKE NO RESPONSIBILITY IF YOU BRICK OR DAMAGE YOUR DEVICE!

Problem 1 - No LTE

No LTE, 3g works fine, but when you get an LTE Connection you don't get an IP. This is an APN problem. LTE Works fine on stock, but not on SlimKAT / CM11 (tested).

Solution:  You have to activate on stock (you should have a nandroid right?). After you've got everything working on stock you have to backup your APN list, then flash your custom ROM.
Next you have to restore your APN list, reboot and LTE will work! Unfortunately it's harder to do than it seems. an unprivileged app can no longer write to the APN list. So here's my solution (you may or may not need to do this on stock to read them):

1. Make sure your phone is rooted (and has supersu or something on it)
2. Install APN Backup and Restore from the Play Store.
3. Install ES File Explorer File Manager from the Play Store.
4. Launch ES File Explorer and in the setting enable "Root Explorer"
5. Navigate to "/data/app" and long press and "cut" "com.riteshsahu.APNBackupRestore-1.apk"
6. Navigate to "/system/priv-app" and paste the apk file there. 
7. Long press on the apk and hit properties. Permissions should be "rw-r--r--" Owner and Group should both be "root"
8. Reboot
9. Open APN Backup and Restore, close the ICS warning, hit menu, then disable ICS checking.
10. Now you can backup and restore your APN's

Notes:

• If you're restoring you may want to make a backup, delete the APN's that came with your ROM, then restore the stock ones. 
• You may need to find and move the stock file with ES File Exporer if it didn't save to "/storage/emulated/0/ApnBackupRestore". 
• I don't recall where it saved them on stock, but you may want to find it and make sure it's not going to get deleted when you flash. 
• Reboot when you're done.

 Problem 2 - VOIP Apps use top microphone

I fought with this for quite a while, in the freedompop messaging app I could turn on various settings and it would work until they updated the app, then it would require a different set of options. I thought it was a freedompop problem until I started playing with the new Google Hangouts. It only used the top microphone, and there were no options to fix it.

Solution: It's a build.prop issue.

1. Install Build Prop Editor From the play store. (or use whatever method you want)
2. Change "persist.audio.handset.mic" from "digital" to "analog"
3. Reboot 

Note: I removed some lines in "/etc/audio_policy.conf" related to VOIP before finding the build.prop issue and it didn't fix it. But it may have changed things, I'm looking into this.

UPDATE: Just confirmed from my brother - the build.prop edit fixes the problem.

Problem 3 - Amazon Music Won't Play Downloaded Prime Songs

Symptoms: Streams Prime music fine, plays music I've bought and downloaded, plays MP3's from the phone fine, crashes when trying to play Prime Music I've downloaded.

No solution so far.