Root [Guide] Fixing LTE you lost after flash

[tytyty1]

CURRENT STATUS OF GUIDE: COMPLETE contains multiple methods used to fix LTE on our phones.
This will be a thorough guide explaining how to restore LTE to your phone. I am posting it right now because I see a handful of people posting the same thing and nobody providing a universal solution so I am providing all of the tricks/methods used to get your LTE back working. This should work regardless of if you have Boost, Virgin, or Sprint. I'm currently uploading all the files I will be including in my guide to dropbox to make things easier and a bit more organized if you have trouble finding anything in other threads or if the links expire.

THINGS TO KNOW
-CMx roms and other open source roms WILL NOT LIKELY EVER CONNECT TO LTE AS WELL AS THE STOCK ROM. That doesn't mean they cannot get a decent LTE connection however.
-Dirty vs Clean Flashing makes ALL the difference in the world when it comes to these phones and their connections
-Your phone wont always establish an LTE connection immediately after flashing so be a little patient
-This guide is only to help you if you lost LTE on you volt due to flashing
-This will provide individual methods to attempt fixing your LTE and an ALL in one guide
-WHILE MY ONLY INTENT IS TO HELP, I AM NOT RESPONSIBLE FOR ANY DAMAGE YOU MAY CAUSE TO YOUR DEVICE.

GUIDE Methods to fixing LTE
FOR ALL
-If you simply want your LTE working back at its best then you will need to revert to the ZV5 Stock Rom
The stockrom has the APN settings for ALL 3 networks and when it first launches it learns which network you are on and "dresses" your phone accordingly or so to speak.
-Boot into CUSTOM RECOVERY (Power Off,Hold Vol-down and power until words show up and let go/ boot from an app like flashify(Root needed)/boot from advanced power options(found in dev options then by holding down power)
-factory reset(dont have to wipe internal memory or external)
-wipe cache and dalvik cache
-install ZV5 Radio (IF YOU DON'T HAVE IT)
-install ZV5 StockROM (we're gonna use odex just for the sake of not running into issues)
-after first launch a bunch of stuff will pop up(when the connections optimizer dialog pops up just close it by hitting back, I allow iZat just for the hell or it. Otherwise the rest of the stuff I would say ignore unless it activates itself.
-If after about 5 minutes LTE doesn't appear(in an area you know certainly does) then go to settings>system updates>update PRL then Update profile
-after updating prl and or profile sometimes they have errors so you may have to try multiple times and sometimes you temporarily lose data connection while updating it but it will restore.
-restart phone
- make sure wifi is off and nfc is off and data is enabled
-dial your voicemail and hang up shortly after
-if you still dont have LTE go to dialer and use ##873283#
after that is finished the phone should restart and possibly check for one more update and then LTE should appear not long after.

ON STOCK(Incomplete but follow above)
settings>system updates> Update PRL then Update profile

If updating the PRL doesn't fix LTE or you can't update the PRL then do a clean flash of the rom or ZV5 Stockrom and then update the PRL again and LTE will restore. Then do a clean flash of the desired ROM along with the APN fix(try it after first boot and if that fails try it right after flashing.

-dial to self activate may re-enable LTE ##873283#

ON CM1x ROM(incomplete but some solutions)
To my knowledge APN fixes or dirty flashes are the only current way of making LTE work but because of the nature of CM even then the connection still isn't generally as aggressive(although some developers do the best to make it so and in some cases possibly better)

-Flash the APN fix right after flashing the rom(Boot into rom first then go back to recovery and flash fix for 4.4.4+) then go into your settings, enable root permissions through developer options(Apps and adb) find where you can change the APNs and simply select the correct one and if that doesn't work after leaving menu(also make sure wifi is off) try again by toggling another apn(possibly the wrong one) and it should revert to the proper APN.

-If nothing seems to work you can always flash back to the Stockrom(ZV5 works)

-If you are bricked or STILL can't figure it out how to get your LTE back then downgrade to zv3 using the LGFlashTools, ZV3.tot, and LGUnitedMobileDrivers and following this guide

-On some CM roms I noticed my LTE would appear when I would mess with certain other toggles that are unrelated such as a hotspot toggle enabled LTE for me

-CM roms tend to have issues with sending/receiving MMS with the stock messaging app. Some 3rd party apps such as Textra work great for fixing this!

---DOWNLOADS---
BOOST APN FIX
SPRINT APN FIX
VIRGIN MOBILE APN FIX
Textra(for mms in CM roms)
LGFlashTool(For downgrading)
LGUnitedMobileDRIVER(For downgrading)
ZV3.tot(unzip first for downgrading)

 

[tarheel418]

Do i have to downgrade to zv3 from a zv5 to root my lg volt zv5? I'm very confused reading all these questions. Thanks to anyone who can help and knows what they are talking about.

 

[tytyty1]

Do i have to downgrade to zv3 from a zv5 to root my lg volt zv5? I'm very confused reading all these questions. Thanks to anyone who can help and knows what they are talking about.

Yes. First downgrade to zv3. Use towelroot and then install custom recovery and install a rooted zv5. It may be possible to do it without downgrading but the easiest way is to downgrade and upgrade again.

 

[kwknott]

No you can root ZV5. Go to root guide and try either method 2 or 3

http://androidforums.com/index.php?threads/893332/

 

[NeoZiggy]

I noticed my LTE kept dropping out and I would have to go into APN settings and reselect the boost APN a lot.

So I removed the Sprint APN information and added a value "prefered" at the end.

I haven't lost 4G LTE yet for over 24 hours even after rebooting. I had sent a test MMS and it worked.

<?xml version="1.0" encoding="utf-8"?>
<apns version="8">
<!-- Boost Mobile -->
    <!-- BOOST MOBILE APNS -->
    <apn carrier="Boost_Mobile" numeric="310120" mcc="310" mnc="120" apn="n.boost.ispsn" user="" server="" password="" proxy="null" port="null" mmsproxy="68.28.31.7" mmsport="80" mmsprotocol="null" mmsc="http://mm.myboostmobile.com" type="default,supl,mms,fota,dun" bearer="14" preferred="true" />
    <apn carrier="Boost_Mobile" numeric="310120" mcc="310" mnc="120" apn="n.boost.ispsn" user="" server="" password="" proxy="null" port="null" mmsproxy="68.28.31.7" mmsport="80" mmsprotocol="null" mmsc="http://mm.myboostmobile.com" type="default,supl,mms,fota,dun" bearer="13" />
    <!-- END BOOST MOBILE APNS-->
<!-- END Boost Mobile-->
</apns>

The APN file is located at:
/system/etc/apns-conf.xml

After editing (I used FX file manager) and saving the file you'll have to go into APN settings, press menu (top right corner) and select 'Reset to default', then select the top APN, press Back to go back, press home and your done.

You'll still need to flash the APN fix before doing this. This is for Boost Mobile. For other carriers, remove the Sprint lines and leave the ones for your carrier and add preferred to the end of the LTE line.

Hope this helps. If you mess it up (and forgot to make a bkp) just reflash the APN fix.

 

[dvdavid888]

Can someone with the preferred-apn.xml settings for Sprint prepaid post

 

[bg4m3r]

Can someone with the preferred-apn.xml settings for Sprint prepaid post

There are APN fixes in step 7 of the deprecated rooting guide.
http://androidforums.com/index.php?posts/6842076