Synergy ROM for AT&T/T-Mobile/Verizon Galaxy S3! [Multi-Window]

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For this week’s ROM of the week for AT&T, T-Mobile, and Verizon Galaxy S3, check out the latest version of Synergy ROM. Previously it was a bit buggy I admit(on non-Verizon versions) but the latest version I tested works quite well with full multi-window on AT&T, T-Mobile, and Verizon Galaxy S3s. It’s supposed to work also on Sprint Galaxy S3 but I have had some troubles as shown in video overview.

I know there’s currently few ROMs that offer you full multi-window on the AT&T and T-Mobile Galaxy S3 but the Synergy ROM is one of the few that do and hence a great option for those of you on AT&T and T-Mobile. Also, you do have to flash an extra contacts fix file for AT&T or T-Mobile otherwise you will get a force close error with contacts and not able to make calls (I found out) but after flashing the patch, I’ve had zero problems since then, everything working pretty darn smooth.

Synergy ROM does offer overclocking up to 1.9Ghz but I do recommend around 1.6-1.78Ghz OC for optimal performance and battery life.

Wifi tethering works with its on-board Wifi Tether Treve app, just set SSID and Wifi Encryption and you are set to go.

Also Synergy ROM does offer both Android 4.2 Photo Sphere Camera and Note 2 Camera, something I really love about Android 4.1.2 ROMs.

If you really need multi-window, overclocking, and two cameras on your AT&T, T-Mobile, or Verizon Galaxy S3, give the latest Synergy ROM a try and let me know what you think. (Don’t forget to rate the ROM at bottom of this post after trying!)

Overall, I have to hand it to the Synergy ROM developers who are the first to bring fully-working, stable multi-window to AT&T and T-Mobile by porting Verizon ROM, thanks again guys and don’t forget to donate to these devs.

For installation, see the latter part of the video which guides you through.


Download Synergy ROM for AT&T/T-Mobile/Verizon Galaxy S3
Download Contacts Fix Patch for AT&T/T-Mobile Galaxy S3 (MAKE SURE YOU FLASH THIS AFTER INSTALLING ROM!!!)

For installation, please refer to the latter part of the video and make sure you flash Contacts Fix Patch for AT&T/T-Mo users!
For T-Mobile/T999 users, please flash KTweaker kernel after installing ROM!

Credits – XDA <--- Please donate to the developers of this ROM if you like it, thanks!

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112 Responses

  1. ALex nater says:

    I have a 747 but i galaxy s3 mistakenly install a room that was not the galaxy turns not only does nothing when I plug noise is hopeless

    • Max says:

      I did that with my T-Mobile GS3 couple weeks back, installed a GS2 ROM on GS3 and bricked, I sent it to Mobiletechvideos and they fix it for like $60, got it back in about a week, working fine again, here’s the link:

  2. revor says:

    Where is the file

  3. Ryan says:

    Max, either I’ve had too many beers tonight, or you didn’t include a download link for the contacts file. My apologies if I missed it somehow.

    Anyway, the contacts file can be downloaded here:

    Happy flashing!

  4. Juan says:

    I have two problems with this rom the wifi im not able to used my home internet

  5. fabian says:

    its stuck on the activating screen any help?

  6. Sunny says:

    cant get to wifi to work on galaxy s3 t-mobile

    • Max says:

      whats the error? Does it hang? or does wifi don’t turn on at all?

      • Kenny says:

        No it don’t turn on

        • Max says:

          Try installing KTweaker kernel for T999 here:

          XDA thread:

          Not sure whats happening but kernel should fix I think.

          • Juan says:

            Thank you it work perfect now you the best

          • juan montero says:

            Hey max I went to xda forums and tried to do the following (If you are using my ktoonservative governor with the Touchwiz JELLYBEAN version, you should rename /system/bin/qosmgr to /system/bin/qosmgr.bak to prevent battery drain) but for some reason I cant rename it any input on this would help

  7. kevin says:

    Hey max I just wondering were the link was for verizon gs3?? And could u send me the link for a good kernel for this rom??? Thanks!! Keep up all the good work.

  8. juan montero says:

    i currently have a gs3 t999 i did everything you said to do so far every thing is working great
    except not getting 4g only 3g and H+ what can i do to fix this i did factory reset wipe data
    wiped cache what else is there to do?

  9. juan montero says:

    hay max for t999 i set preferred network mode to gsm/wcdma/lte correct ? well Ive done this and still getting same results 3g and H+i would love to have 4gon there please help

    • Max says:

      This ROM may give 3G even if you get HSPA+, check your settings->about device->Status to see what connection you really on. This is because its a Verizon-based ROM that’s been ported so you actually are getting HSPA.

  10. Sudheer says:

    I didn’t find any where on what version of android is this custom ROM providing? Not in the description or not in the video. Can some one let me know please?

  11. alan says:

    Hey mark I have the T-Mobile t999 but for some reason when I install this ROM it changes my model into the sprint model and is reading it as sprint??

    • Hales says:

      Same for me. At first I had no data access either. Theres a synergy update that came out today, though. I flashed that and at the end of installation I checked the status. It said something like I have d2spr and if not I used the wrong recovery. Only one rom for all but I’m def tmo not spr. Whatever the constant error popups about and such stopped, so thats an improvement.

  12. Scott says:

    AT&T I747 S3. After factory reset, wipe, and install, on boot every few seconds, a apps crash. Even after every reboot. Everything on the phone seems to work but this very frustrating.

    Anyone else get this or comments?

  13. Ebad says:

    Hey Max.. I tried out the last synergy rom on my canadian gs3 i747m and i was having some issues. I wanted to know if this rom will work fine so that I can try it out ..

    • Max says:

      It should be fine, working fine on my i747 but there may be issues as some people are pointing out, this ROM isn’t perfect but it does give you stuff like multi-window now if you don’t like waiting.

      • Ebad says:

        Yeah I tried it out and I was constantly facing the error popping up so I flashed the Jedi invasion rom back.. Still waiting for the stable version of any rom with Multi window and the latest camera features

  14. Samuel says:

    I have just put this ROM onto my AT&T S3 I747, did a factory reset, cleared the caches and installed the ROM and the contact fix but every time I try to open play store it opens for a second and get a loading screen with the loading thing spin for maybe half a second, freeze, and then play store crashes. I have tried wiping the caches and fixing permissions but it doesn’t help. I am also having problems with the lock screen. I set it to pattern lock but it still stays as the swipe unlock no matter what I do. This issue is relatively minor to the play store issue though and would like any kind of help someone can offer me. Thank you.

    • Samuel says:

      Nevermind about the lock screen issue just me failing

      • Samuel says:

        I now have everything working completely fine except contacts… I installed the contacts fix .zip and it hasn’t done anything. Please help this is the only thing that isn’t working on this ROM and I really want to use this ROM but I need the contacts app to work in order to use it as a phone.

  15. Anthony says:

    Is anyone else is having battery drain issues… I love this rom but the battery is becoming a huge buzz kill its draining much to quickly 🙁

    • Jerry says:

      try to lower the processor to around to 300 mhz in the minimum frequency (found in the app called KTweaker that was installed with KTweaker kernel or you can use SetCPU that can be found on playstore)

  16. Andrew says:

    Hi Max, I’m a newbie and rooted my att S3. I tried the Synergy Rom and did all the process until the end where is verifies all info and notice that its giving me under device is d2spr. I checked your video again and yours shows d2att. Am I doing something wrong? Thanks.

  17. Alex Oller says:

    Steps that got it working on Galaxy S3 T-Mobile T999:
    * 1- Download the ROM and install according to the instructions,
    Do a data wipe/factory reset, data cache wipe and Dalvik cache
    wipe. (Note: it is not necessary to apply the contacts fix. Seems to be
    working okay now.)
    * 2- Download KTweaker and immediately flash it after the
    Aroma installer has finished. (Stay on the recovery console before you
    Reboot the first time so you can run the ktweaker kernel.
    * 3- Follow the initial setup upon first boot and enjoy.
    To fix the battery drain, download a utility to browse to your
    Files like root browser from the Google store and navigate to
    /system/bin/ and rename the file qosmgr to qosmgr.back
    Reboot and you’re all set. This is a great stable and smooth ROM
    I recommend it as a daily driver. Very happy with it!

  18. Steve says:

    i installed this on my att s3 747 and i cant get data to work. everything else works fine. Can someone please help me with this?

    • Alex Oller says:

      @Steve – Did you install a different kernel like ktweaker? Try that i. fixed that problem for me with the T999.

      • Steve says:

        @alex yeah i installed ktweaker after i installed the rom.

        • Alex Oller says:

          @Steve – Okay.. that should’ve fixed the problem. Try running fix permissions then bootinto recovery mode and flash the ktweaker again, then immediately
          wipe the cache partition and Dalvik cache before you reboot. Then go
          ahead and reboot and see if that fixes your problem. Also when you
          first go in select your network in the settings as Gsm/CDMA/Lte and set the
          The default to auto for gsm/CDMA/lte. It should come up after
          A few minutes. Hope this helps.

    • Samuel says:

      I read this somewhere on the xda forums and it worked for me. What I did is you got to settings, more settings (at the top), mobile networks, make sure the network mode is set to GSM/WCDMA/LTE, then got to access point names, then press on ATT LTE but don’t mark it with a green dot and change the APN to pta, then do the same for ATT US HSDPA and mark this one with the green dot if its not marked already (don’t know if it matters but mine is working fine now and wouldn’t want to mess with it) just change the APN to pta. Hope this helps you like it did for me 🙂 I am also having trouble with the contacts not working even after installing the contacts fix .zip but for now I am using a third-party app contacts+ which is working fine. If you can help me, great I just want to make sure everything is working as smoothly as possible (kind of OCD in that sense I guess) but if you can’t I’m alright.

      • Steve says:

        @samel when i went into my apn settings it was empty and i tried making a new apn but it wouldnt let me enter anything in.

  19. Bryan says:

    Unfortunately, the process com. has stopped

    Unfortunately, the process com. has stopped.

    Unfortunately, com.sec.
    sprextension has stopped.

    help me please

    • Steve says:

      Go to mobile network settings and select gsm/cdma/lte a few times it should fix the problem. But when you reboot the messages are going to pop up again so repeat the same steps.

  20. juan says:

    Battery is drain really fast please help

  21. juan montero says:

    im having the battery drain problem too and im still not getting 4g only 3g and H+ keeps switching back and forth someone help please.

  22. mike says:

    rooted gf s3..factory reset & wifi not turning on..need help please before she kills me lol

  23. juan montero says:

    hey mike install the KTweaker kernel that worked for me gs3 t999

  24. juan montero says:

    has any figured out how to fix the 3g/H+ problem for gs3 tmobile t999 need help getting the 4g back

  25. tony says:

    I installed the synergy rom n so far its good. Question is I woke up this morning n had a Samsung update waiting at 157mb Pretty sure not wanting to install it am I right. Im on a AT&T galaxy S3

  26. David Randolph says:

    My AT&T voice mail does not work now. That’s a big problem. I get a Verizon message that says i dialed the wrong number. Does anybody else on AT&T gets this? Can’t seem to find a perfect ROM!

  27. David Randolph says:

    I discovered a flaw in the contacts update! For the voice mail butten it has 11 in front of my number instead of just 1. Also, when i click on voice mail in my contacts it is *08 and get an error and does not dialed out!

  28. David Randolph says:

    I have to dial my number manually to get to voice mail or use Google voice. Please let me know if their is a work around. I tried to change the number, but it keeps reverting back to the default +11.

  29. Loran says:

    Yeah so i am in Canada, And this ROM is garbage I followed video, reasoning for being garbage tooooooo many bugs here is my Pros and Cons.
    -Centre clock, yeah thats about it.
    -takes to long to install
    -checking and unchecking global APN does not fix activation, you need to check bypass activation,what if i want my phone activated.
    -non and i mean non of my performance tweaks got installed for some reason that was the whole point i installed custom ROM.
    -play store does not work at all, Have the same issue as previous poster above.
    -ROM will not let me add a google account non of the 3 i have.
    -and finally dual screen or two apps on one screen what ever the tech name is is not working at all either.

    Well that is it for now these bug where found in the first 2 minutes of playing with ROM i am sure there is a tone more but i am restoring a back up as i type i am not giving this ROM no more time of my life to prove its self.

    Any one else having issues don’t be shy to add to my CONS list and PROS if you can find any more lol.

    In my opinion this ROM is the shitz\Garbage horrible ROM more testing and R&D needed.

    • Loran says:

      so i just re-watched the video and there is no performance menu my bad, but my opinion still the same synergy’s previous ROM was may better and had a lot more options in the performance area. including oveclocking to 2.1 GHZ not the 1.9 GHZ in this ROM. booo i give this ROM a FAIL ALL AROUND.

  30. DeWayne says:

    Hi, does anyone know how to get out of boot recovery loop. I installed The Synergy rom on my tmobile galaxy s3 and followed all the steps. When I pressed the reboot option, it keeps looping back into CWM Recovery. … PLEASE HELP!

  31. juan montero says:

    I went to xda forums and tried to do the following (If you are using my ktoonservative governor with the Touchwiz JELLYBEAN version, you should rename /system/bin/qosmgr to /system/bin/qosmgr.bak to prevent battery drain) but for some reason I cant rename it any input on this would help does anybody else have the some problems I have a gs3 t999

  32. juan montero says:

    gs3 t mobile t999 somehow changed to SPH-L710 how to fix i installed Synergy ROM for tmobile i dont know what went wrong someone please help me

    • juan montero says:

      never mind i fixed it using mobile odin pro thank god i was able to run Google play store download mobile odin pro and reinstalled stock firmware through there. whats weird is i couldn’t use odin on my pc kept getting (fail) for trying to install stock firmware. ifind that kinda odd. just thought i let you guys know just in case someone runs into the same problem.

      • juan montero says:

        also I’ll naver try to install Synergy ROM again i give it a biggggggggggg thums down

        • juan monteto says:

          I was up to like 4 in the morning trying to fix this but it worked and I’m glad it did now I’m using the the galaxy mod ROM works bratty good just needs a little work

    • tony says:

      My AT&T sgh-1747 was also changed to the SPH-L710 but it hadn’t affected me in anyway looks like to me, but my question is i guess is there anyway to get it back to saying SGH-1747 and not have to redo rom?

      • juan monteto says:

        You’ll hove to use mobile Odin pro and flash stock ROM for your AT&T sgh-1747 my phone was not working at all but some how I managed to be able to download mobile Odin pro from the play store and I already had my stock ROM saved on my PC so I just put it in SD/ download and then went to mobile Odin pro click on open file then shoose SD then go to download and find your stock firmware that you downloaded it will ask you to extract it then go back and open file again and find the extracted file it should be in the same place as the other file is good luck.

  33. Alex says:

    Someone help me my data is not working anymore. It was working fine but now it won’t turn on please help I really like this rom. Also I have been using the rom for a couple of days now and the data was working fine I also installed a different kernel too.

    • Rjam says:

      go to Google Play, download APN Manager Pro via WiFi ($1.40). Put in your APN manually and it’ll work. This worked for mine as well.

  34. Anon says:

    do you have rom on 4.1.2 jellybean for s3 mini rooted ? Max
    Based version

  35. Aamir says:

    i have s3 t999 did a factory reset installed the rom it boots to recovery everytime does not boot to the menu

  36. WaSsAP says:

    I was testing this ROM and too many FC on stock camera and jb camera/gallery apk awhile video on front device…worthless!!!!!

  37. Jason LaBossiere says:

    I am having a issue with is not allowing me to change the access point name. Why wont it allow me to do this?

    I need to set it to my carrier Solavei. Can someone tell me how to edit it as it will not let me change anything.

    • Jason LaBossiere says:

      I am using the T-Mobile version by the way.

      • Android TV says:

        We were actually able to fix this the ability to permanently add another pre paid carrier by going into the file path synergysetup/carriers.

        There are 2 files that has to be edited global-apns-conf.xml & apns-conf.xml under the d2tmo file.

        if you want your T-Mobile phone on Solavei just simply ad the code setting to the bottom of the first file like so in the first file
        and like so in the second file in the t-mobile folder
        <apn carrier="Solavei"

        Hope this helps. This can also work for any carrier.

  38. endlesstalkwireless says:

    Hey Max,
    I have done everything you said on how to install this rom, but I`am getting alot of force close on apps and no data. What should I do?

  39. Erikwu says:

    hi max
    do you know any rom has chinese system for canadian sgh-i747?

  40. Simeranjeet Sandhu says:

    I flashed this rom on my Tmobile Galaxy S3. & com.sec.sprextension both keep stopping. I flashed the kernel and contacts fix right after. Any idea whats wrong?

  41. Joey says:

    Hi Max, I’d installed this rom and everything seems to be working GREAT! except my Bluetooth. Nothing can connect that worked before. Does anybody else have/had this issue? Thanks in advance.

  42. WaSsAP says:

    New synergy Roms out there released march 21st most bugs fixed alike limit to MMS camaerder fixed…. 🙂

  43. titan says:

    HI, does anyone know if the needs to be placed in the external SD card? I stored it in internal SD, flashed the phone and got an error message for not working

  44. Garrett taguchi says:

    Anyone else notice that scrolling through Facebook is very jerky? I motored this with the previous synergy build…. Its super annoying.

  45. seshu says:

    This rom is awesome. It Is my daily driver. Absoultely no issues. Battery awesome.
    Only issue so far is voice mail does not work. Manually typing number.

    I had play store fc error in ths begining but I tried using diffrent accojnf and come back to my own account. It worked.
    This is only rom I have seen so far working flawlessly with multiwindow.
    Thanks creators. Excellent work.

  46. Daniel says:

    Recently installed this rom on att i747, installed the contacts fix, and already waited more than 30 minutes and it is still not working. Is there any workaround?? I really want to give this rom a try and this is the only thing that is not working other than that rom works smooth.

  47. tony says:

    Hey try out the updated version of synergy its r420 and was released thursday.. dont have the problems this one does and dunno if this affects everyone, but i installed it with the Ziggy Kernel Friday morning and noticed an few problems like one time had to take battery out cause screen wouldnt respond to any button push and being slow about coming up from sleep. Anyway I redid it this morning and used the stock kernel and have no problems now. BTW i have a AT&T SGH-1747

  48. D. Hill says:

    I can see my POP3 email, but it doesn’t open in the email app?


  49. DAN FRAZIER says:

    After you install the ROM before you reboot do fix permission dirtyflash fix it works for all the crashes only problem I have is MMS don’t work can’t send or receive any picture mail.

  50. DAN FRAZIER says:

    After you do the install run dirtyflash fix before you reboot. Only problem I have is my MMS don’t workccan’t send or receive any picture mail.

  51. Eliot says:

    Hi I have been following your site ever since I purchase my S3 a year ago, I think I was one of the first one who bricked the t999 by installing an international version rom but thanks to you I got it fix with mobiletechvideos. I installed several roms in my s3 and jellybam seems to be the best and fastest but tethering does not work on Tmobile, so far Synergy is the only one I have tested in which works. Do you know of any 4.2.2 whci supports tethering on TMO?

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