Credits:
Havealoha and his team for CM12.0 5.0_rc1.
Wopema71 for his how-to guide that got me started.
Sileshn for his updated melius-common and kernel repo's for this amazing phone.

/*
 * Your warranty is now void.
 *
 * We are not responsible for bricked devices, dead SD cards,
 * thermonuclear war, or you getting fired because the alarm app failed. Please
 * do some research if you have any concerns about features included in this ROM
 * before flashing it! YOU are choosing to make these modifications, and if
 * you point the finger at us for messing up your device, we will laugh at you.
 *
*/

NOTE 09.10.15 - The APN issue may not be a problem.  Leaving APN's Bearer setting unspecified will allow the system to automatically move to the correct radio APN.
 OLD  BUILD 09.10.15 - (cm-12.1-20150910-UNOFFICIAL-meliusltespr) LMY48G

NOTE 09.13.15 - The new LVY48F build has not been thoroughly tested by me yet.  It booted a little slow and sluggish after upgrading to the latest build.  I then tested a clean install and had no problems.  I tried a newer gapp as well and had no problems.  I restored my backup, cleared the cache, and then installed the LVY48F build.  After a few minutes and letting it settle I rebooted and its running great!
 WARNING  - I managed to end up in a bootloop after installing Deep Darkness Theme. I restored a BACKUP and will look into the problem tomorrow. Others have had this problem on different phones. Remember to always do a backup before making major changes to your phone.
NOTE 09.13.15 - Deep Darkness boot animation caused the problem. I've tried other themes without the boot animation bootloop. You can use the Deep Darkness theme but DO NOT select the boot animation.
 OLD  BUILD 09.13.15 - (cm-12.1-20150913-UNOFFICIAL-meliusltespr) LVY48F

NOTE 09.15.15 - The 09.13.15 Build was unstable.  This version should correct some of that and power consumption.  If you installed the 09.13.15 build just flash/install this over it.
 OLD  BUILD 09.15.15 - (cm-12.1-20150915-UNOFFICIAL-meliusltespr) LVY48F
NOTE 09.23.15 - Flash this zip file after flashing or if you have already flashed 09.15.15 build. (DO NOT CLEAR CACHE)
 UPDATE  for 09.15.15 build - update.zip (Fixes audio and enhances UI, network, and media settings)

NOTE 09.24.15 - Improved audio, video, and network settings. Smoother user interface and faster optimization.  Please clear dalvik/art cache.
 OLD  BUILD 09.24.15 - (cm-12.1-20150924-UNOFFICIAL-meliusltespr) LVY48F

NOTE 09.27.15 - Improved benchmark by +3200 points. Upstream merge.
 OLD  BUILD 09.27.15 - (cm-12.1-20150927-UNOFFICIAL-meliusltespr) LVY48F

NOTE 10.04.15 - LiveDisplay fixed and Cyanogenmod updates. Stock and Overclocked Kernel updated.  You may switch to AwesomePlayer in Developer Options if you would like.  Default is NuPlayer.
 OLD  BUILD 10.04.15 - (cm-12.1-20151004-UNOFFICIAL-meliusltespr) LVY48F
 OLD  KERNEL 10.04.15 - (OVERCLOCKED) Kernel_OC_10042015.zip / (ORIGINAL) Kernel_STOCK_10042015.zip

NOTE 10.12.15 - Cyanogenmod and Kernel updates and upstream merge.  Proximity check and IO Scheduler settings changed.
 OLD  BUILD 10.12.15 - (cm-12.1-20151012-UNOFFICIAL-meliusltespr) LVY48W
 OLD  KERNEL 10.11.15 - (OVERCLOCKED) Kernel_OC_10112015.zip / (ORIGINAL) Kernel_STOCK_10112015.zip

NOTE 10.18.15 - Upstream updates and new SELINUX Enforcing / Permissive Switch.  You can set the Mode with SELinuxModeChanger in your Apps.  You can see the Status in Settings > About Phone > SELinux status.  Links to information about this feature - Link 1, Link 2.
 OLD  BUILD 10.18.15 - (cm-12.1-20151018-UNOFFICIAL-meliusltespr) LVY48W
KERNELS:  Kernels have not changed since 10.11.15.

NOTE 10.28.15 - ROM: Cleanup and upstream updates.  KERNEL: Bug fixes, cleanup, and upstream merge.
 OLD  BUILD 10.28.15 - (cm-12.1-20151028-UNOFFICIAL-meliusltespr) LVY48W
 OLD  KERNEL 10.28.15 - (OVERCLOCKED) Kernel_OC_10282015.zip / (ORIGINAL) Kernel_STOCK_10282015.zip

NOTE 11.04.15 - ROM: Added adaptive LMK, dex2oat thread count, and upstream merge (LMY48Y).  KERNEL: (low memory killer / vmpressure) changes and upstream merge.
IMPORTANT - Please wipe dalvik/art cache and cache before flashing the new build.
 OLD  BUILD 11.04.15 - (cm-12.1-20151104-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 11.04.15 - (OVERCLOCKED) Kernel_OC_11042015.zip / (ORIGINAL) Kernel_STOCK_11042015.zip

NOTE 11.12.15 - ROM: Upstream merge.  KERNEL: Upstream merge.  I have re-installed my OS and re-installed my compiler libraries.
 OLD  BUILD 11.12.15 - (cm-12.1-20151112-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 11.12.15 - (OVERCLOCKED) Kernel_OC_11122015.zip / (ORIGINAL) Kernel_STOCK_11122015.zip

NOTE 11.18.15 - ROM: Added libraries for Netflix and upstream merge.  KERNEL: Upstream merge.
 OLD  BUILD 11.18.15 - (cm-12.1-20151118-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 11.18.15 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_11182015.zip

NOTE 12.09.15 - ROM: Upstream merge.  KERNEL: Upstream merge.
 OLD  BUILD 12.09.15 - (cm-12.1-20151209-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 12.09.15 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_12092015.zip

NOTE 12.17.15 - ROM: Upstream merge and fix for wired headset.  KERNEL: Upstream merge and modification to kernel governor.  OC Kernel reverted back to 11122015 Stable, this fixes several problems.
Xposed: For those using Xposed Framework I have added the latest version (v78) to the Mega folder.
 OLD  BUILD 12.17.15 - (cm-12.1-20151217-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 12.17.15 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_12172015.zip

NOTE 12.31.15 - ROM: Upstream merge.  KERNEL: Upstream merge.
 OLD  BUILD 12.31.15 - (cm-12.1-20151231-UNOFFICIAL-meliusltespr) LMY48Y
 OLD  KERNEL 12.31.15 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_12312015.zip

NOTE 01.07.16 - ROM: Upstream merge, security update and new version.  KERNEL: Stock upstream merge, OC no change.
 OLD  BUILD 01.07.16 - (cm-12.1-20160107-UNOFFICIAL-meliusltespr) LMY49F
 OLD  KERNEL 01.07.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_01072016.zip

NOTE 01.20.16 - ROM: Upstream merge, no new security updates.  KERNEL: Stock upstream merge, OC no change. 
 OLD  BUILD 01.20.16 - (cm-12.1-20160120-UNOFFICIAL-meliusltespr) LMY49F
 OLD  KERNEL 01.20.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_01202016.zip

NOTE 01.28.16 - ROM: Upstream merge, no new security updates.  KERNEL: Stock upstream merge, OC no change. 
 OLD  BUILD 01.28.16 - (cm-12.1-20160128-UNOFFICIAL-meliusltespr) LMY49F
 OLD  KERNEL 01.28.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_01282016.zip

NOTE 02.10.16 - ROM: Upstream merge, security update and new version.  KERNEL: Stock upstream merge, OC no change. 
 BAD  BUILD 02.10.16 - (cm-12.1-20160210-UNOFFICIAL-meliusltespr) LMY49G
 BAD  KERNEL 02.10.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_02102016.zip

NOTE 02.11.16 - ROM: Corrected previous versions bad blue-tooth and random reboots.  KERNEL: Stock upstream merge, OC no change. 
 OLD  BUILD 02.11.16 - (cm-12.1-20160211-UNOFFICIAL-meliusltespr) LMY49G
 OLD  KERNEL 02.11.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_02112016.zip

NOTE 03.03.16 - ROM: Upstream merge, security update and new version.  KERNEL: Stock upstream merge, OC no change. 
 OLD  BUILD 03.03.16 - (cm-12.1-20160303-UNOFFICIAL-meliusltespr) LMY49G
 OLD  KERNEL 03.03.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_03032016.zip

NOTE 03.10.16 - ROM: Upstream merge and new version.  KERNEL: Stock upstream merge, OC no change.
NOTE 09.08.17 - DO NOT INSTALL Greenify as it will cause a boot-loop.  If installed please restart in TWRP recovery and use the following command using adb to uninstall Greenify from command prompt.  adb uninstall com.oasisfeng.greenify
 NEW  BUILD 03.10.16 - (cm-12.1-20160310-UNOFFICIAL-meliusltespr) LMY49H
 NEW  KERNEL 03.10.16 - (OVERCLOCKED) Kernel_OC.zip / (ORIGINAL) Kernel_STOCK_03102016.zip

 GAPPS  Open GApps - The Open Gapps Project.
 GAPPS  tk_gapps - Selection of different tk_gapps.
 GAPPS  tk_gapps-modular-full-5.1.1-20150913-signed.zip - Located in my MEGA folder.

NOTE: If you have one of these service providers you will need to flash the appropriate update.
 MVNO  Freedompop_fix.zip - Flash this after installing latest ROM.  If you are still having problems please read this POST.
 MVNO  ChinaUnicom-VietnamMobifone_fix.zip - Flash this after installing latest ROM.  Fix found thanks to Wang Xiao.

MEGA folder with all files

** You can also contact me at the xda-developers forum HERE

I suggest trying Trimmer (fstrim) for your android phone.  Its free and requires no special privleges.  I am in no way affiliated with them.  I use the app to clean my phones storage.  I notice a major difference everytime I use it after flashing a new build.

► Bad Build upload - **Fixed
   Thanks to professorfoxx from xda-developers forum for catching the (status 6) error on the uploaded 09.15.15 build.
► Local audio files unable to play - **Fixed - See FIX
   Thanks to JC3_SWADE from this forum for catching the locally stored audio files not playing at all.

** Deleted and Reposting this because of forum structure change.  All forum reply's will now be treated as a reply to the forum itself.  This will keep it organized and easier to read.

MEMBER: JC3_SWADE

First I would really like to thank you for this but I really love my music and I even make music but for some reason I cant play no music not even with the google music app or any other app when trying to play files thats on the phone or sd card Its just so annoying and disappointing but this is the best and most long waited build ever but could you please look into a fix for this for me please??????
 

mmgr - edited for caps

Benchmark results for 09.24.15 build and the latest test build.  From Left to Right.

Benchmarks

Getting better results.

I'm having an issue with getting service. I use Freedompop with the Mega and I tried the switch to Virgin Mobile fix as well as dialing ##72786#. Factory reset didn't seem to fix it either. When I do airplane mode on then off, Sprint appears with an exclamation mark for a few seconds then goes to no service. I tried flashing other modems and the sprint.zip.
Do you happen to know of a fix? Thank you.

Interesting, I may be switching to freedompop in a month after my sprint contract is up.  I believe you can set your APN to freedompop LTE?  Try setting that and reboot the phone.  If not you may need to push the latest stock rom thats in my mega folder using odin onto the phone then do a profile and prl update first.  Then install cyanogenmod with the updated modem.

P.S.  The updated modem will not be erased when you flash philz-touch then wipe the phone and re-install cyanogenmod.

I just put freedompop onto a friends samsung galaxy s3 and did the profile update and prl update.  It took freedompop a good 24 hours before it even provisioned correctly.  Just flipped it on the next day and it showed 4g signal.  I'll probably put cyanogenmod on it tommorrow and see what happens.  I'll let you know how that turns out.

I would personally push the stock rom back onto it from my mega folder and if you are not able to get it working then you may have a locked phone.  If it does work then It's something I am going to need to figure out.

Thanks, flashing newest stock rom and dialing the number to reset seems to have worked.  I see Sprint along with a signal indicator. No more exclamation mark. Sometimes it seems my phone loses the SIM card but I suspect it's my phone's/sim card's issue. I'm using a SIMGLT207R SIM if that matters. Otherwise I'll probably try to get a SIM off of Ting and use that.

Make sure you do the profile and prl update in that order.  If you plan on staying with the latest stock rom you will have to use playstore to install the freedompop extras.  Just type freedompop.  I think 2 or 3 of those listed are required for making the phone work properly on stock.  If you plan on using my cyanogen build let me know if it works.  I won't be able to test it on my phone until after the 14th of November.  I and others could use your experience with freedompop on this forum or xda.  Let us know if it works or not.

I'm testing a new permissive/enforced selinux security switch for the next build thanks to sileshn.

Here is a [link] with an explanation.

Working on the freedompop problem.

Well, that was fun!  Yes, I managed to get freedompop working on a samsung s3.  I created a zip fiile you can flash to enable freedompop on SPH-L600.  (freedompop_fix.zip)

IMPORTANT NOTE!  You can simply change Settings > Mobile Networks > Access Point Names > FreedomPop LTE > APN Type = default,mms - This should enable FreedomPop on the phone.

These are the settings for TING.  Thanks to a private message from a member on the XDA forum

lastnight i sent u private mess in xda forum
this morning i flashed back to stock rom (OH1) then  flashed to your rom again it still can't receive incoming call here is picture 
one more thing when i make a call and tap cancel button it doesn't stop immediately . it said hanging up for 4 or 5s (icludeed picture)

thanhptv93, I've been very busy with my new job and I'm transitioning to a different schedule.  I'll be able to take a closer look at this mid-week.  Right now I'm going to put out a new build that i've worked on earlier this week.  I promise you I will take a look at this as soon as I get the chance.  If you have any more information about your service provider please let me know so I can research it.

I love your work and am very happy with what you've done and are doing. I too cannot receive or make phone calls, they connect but choppy audio is all either side gets. Could be a Sprint problem, just thought I'd share in case it's not. But again , many thanks as you have done amazing work.

kedges, I need more intel on what's going on here before I can help you.  Are you using an mvno like freedompop, ting, etc..  I need your location and as much information as you can give me for me to narrow down the problem.   

I am so sorry for my slow response time the past week +.  Again, I've started a new job and am transitioning to a night shift.  It's taking a lot of time to adjust.  Give me a little time and I'll do everything I can to help both of you out.

P.S.  As far as the new Marshmallow/CM13 - It's on the board.  It will take time.  Thank you for responding and letting me know your loving the ROM!!!!!

thanhptv93,

I havent had much time to take a look at this yet.  I did find some APN information that you can add to Settings > Mobile Networks > Access Point Names > Click the Plus (+) top right.  And insert settings from LINK

I'll be able to do more research on this Wednesday or Thursday.  I'm hoping its just a simple APN tweak.  I may have to add a different RIL and give you details on how to implement it in the /system/build.prop of your phone.

I'm in Arizona. Using straight Sprint - APN : Sprint LTE internet- n.ispsn. I've reflashed the modem nj.1 with no success. Calls will connect but voice from either end are intermitent or not aubible at all. Running OC Kernal 10/04 (tried most recent10/12 but experienced multiple freezes so went back to 10/4) Also on 10/12 build. Let me know if more is needed.  Good luck on the new job!! No hurry or worries.

kedges,  I am at a loss on whats going on here.  Whatever you do don't flash back older modems.  the OH1 is the latest one.  I haven't extracted that yet and made it into a flashable zip.  The only way to install it ATM is to use ODIN to flash the latest STOCK ROM and then use odin to flash philz touch then cyanogen.  You should be ok with NJ1 for now.  I didn't notice a difference betwen OH1 and NJ1.  Intermitent voice makes  no sense at all.  How many bars of reception do you have?  Try dialing *#*#4636#*#* Then select Phone Information - While looking at that information - press volume down + power + home and wait 2-3 seconds.  This will take a screen shot and save it to /sdcard/PICTURES/ScreenShots, if I remember correctly.  Private message me the screenshot.  You can click My Account at the top of this page then File Browser and upload the screenshots there.  I'd like to see the info in that screenshot.

Flashing the freedompop fix on the 10.12 build did the trick! Going to update to 10.18 in a bit. Thanks for your help and all your hard work!

I'm glad it worked!  Wasn't able to test it out myself.  I am loving this 10.18 build, I haven't found one thing wrong with it yet - solid as a rock.

when i installed your rom , it already had a apn setting for my carrier ( i checked all configruations are correct ) so i think it's not  reason why i can't receive any call T.T

thanhptv93,

I haven't forgotten about you.  I did double check and I have no mobifone apn settings.  I'm not sure what settings you looked at.  Will you please give me a screenshot of those APN settings.  I am looking around online to see if any other samsung sprint phones have issues with mobifone.  I know when I was working on freedompop MVNO APN settings I had all kinds of strange problems with making a call, even though I was able to receive them. 

P.S.  Do me a favor and check Settings > Mobile Networks > Preferred network type and try setting it to LTE/GSM/WCDMA or GSM/WCDMA auto.  Also, I'm being very serious here - I do not have mobifone APN settings anywhere on this phone.  Please re-read my mobifone APN post above this.

Can you give me more details about your service provider?  The Radio Interface Layer on this phone is specific to SPRINT.  I need a little bit more information to try and help you.

Wang Xiao, please tell me where you found that RIL.  I would love to compile the source into the next build tommorrow!  I have the next 2 days off to put out the next build.  I think you just made a BUNCH of people VERY HAPPY!  If it only works for some users I'll make a flashable zip.

thanhptv93,

Thank u mmgr for your help !!!

THANK WANG XIAO!!!! I was stumped.  I was going to work on it wednesday/Thursday.  No guarantees I could have figured it out.  I've already messaged a few people in China that have problems.  This is fantastic!  It also works for Mobifone?!?!  I would really like to see the uncompiled RIL.

kedges,

Is it something I should try or will it only work for those in Asia? Let me know. I'm half tempted to try it. It couldn't get any worse. Well maybe it could.

Thats what I'm trying to find out.  I'm working on the next build and it should be ready by thursday night

It's late for me, I've been up for almost 24 hours..  but I'm testing it .. Why not...

P.S. I am using ADB.  So, please wait for me to screw it up before anyone else tries this.

UPDATE: I've pushed the libril.so to the phone - Filesize is different.  I've made a call and text and it works fine.  LTE is still hit and miss on reboot.  I'll test it some more later.  New build should be ready Thursday.

I've removed some unnecessary camera tweaks for the next build.  Honestly, I would use Open Camera over the Default AOSP Camera.  I've never had an issue with Open Camera.

New build is online and tested. Wang Xiao, What rom specificly did you extract that from? Can you give me the link?

P.S. If you cannot get DATA (LTE) or it gets stuck on 3G, set the bearer to LTE then set it back to Unspecified in the APN.  I've had this problem twice now on Sprint service.  It seems to be a tri-band phone problem.