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Google Nexus 5 – Fixing Modem/Cellular Issues on 3/4G Networks

Hey guys Ian here, I pretty much sorted all of these issues on my device so I figured I would let you guys know how to go about fixing most of them.
My theory about the problem has to do with carrier support for fast dormancy on your cellular provider. For those of you that don’t know this is feature
essentially helps your phone and the network preserve your battery life and data consumption when it’s not currently being used. However if you
r network
does not have this feature enabled and your phone has it enabled it can cause all sorts of wacky effects to occur.

There really isn’t anything the carriers can do to fix this issue it’s a problem with Google. They don’t give you the ability to shut it off within ANY
stock menu. There is no USSD code, menu, or APN setting to get this to work the method that I’m posting is the only way to do this I believe.

Beyond the issue of fast dormancy I’ve also included two other simple tweaks to increase your devices cellular performance and also battery life. Just a
warning though I’m not responsible for any damage that occurs to your device so don’t blame me. Also this does void your warranty so make sure if you
decide to send your phone back in for repairs you reset the unlocked boot-loader.

How to Disable Fast Dormancy
This Fix Works For

  • Intermittent Device Battery Drain.
  • Temporary Loss of Connection with Radio Reset Required.
  • Random CID switching (I.E. Battery drain due to your phone constantly switching towers and sometimes complete loss of connection requiring reboot, and or just random cellular data issues).
  • Many more random bugs.
    1. Unlock and Root Your Device
      1. You’re going to need to unlock and root your device, to do this you will need Wugs Nexus Root Toolkit
        1. If your more comfortable doing this yourself feel free to, or following a guide on XDA Devs works too.
          1. First step, unlock.
            1. You need to follow the driver instructions to the T or it won’t work and please don’t ask me for help doing this, when in doubt you’re doing it wrong trust me.
          2. Second step root!.
      2. Now you’re going to need a Root File Explorer
        1. Simple install it from the link provided or use one of your choice.
      3. Now for the run/dangerous part editing the build.prop file!
        1. Navigate to the /system folder on your Android device in Root File Explorer
        2. There should be a file named build.prop
        3. You need to hold the file choice with your finger and select edit with one of the text editors listed,
        4., add this in your build.prop on it’s own line. Sorry about the image Google apparently removed it…

    1. Add those lines to your build.prop and reboot the phone a few times. These lines MUST be exact otherwise your phone will boot loop and you’ll have to wipe and re-install from the toolkit.
    2. That’s it for the fast dormancy, now onto other issues to help more.
How to Get Better Signal Overall
This Fix Works For
  • Poor cellular signal in all areas, or just poor cellular signal in general.
  • Dropping cellular connection.
  • Wireless connection issues.
  • Video Recording related camera issues.
  1. Now you should be rooted and unlocked already, if you don’t want to fix the fast dormancy and just follow this section of my guide then make sure you root and unlock before attempting this.
  2. Next step we’re going to have to select a radio from this page.
    1. I personally will suggest D820 KRT01B (4.4), this is the radio from Android version 4.4 and works on both the US and the EU model of the phone!!! *they are the same hardware just for those of you that are interested.*
      1. Even though I suggest this I will provide a link to the description of all the different radios available, your mileage may vary. Radio list and descriptions here.\
  3. Connect your nexus phone in USB Debugging mode.
  4. Open up the Wugs Nexus Toolkit
    1. In the bottom left launch the advance tools.
    2. Go to the quick tools section on the left, select fast-boot – boot-loader and then click reboot boot-loader.
    3. There should be a directory listed in command prompt to the left of your blinking cursor you’re going to need to copy your selected radio file that you downloaded into that folder.
    4. After it’s copied into the directory you’re going to need to go back to the command prompt that is opened and type “ fastboot flash radio D820KRTO1B.img” *Or whatever your image name is called, obviously without the parenthesis
    5. This should flash your radio quite quickly and it will say that it’s done, after this you simply press the power button and the phone should reboot with the original firmware still intact and the radio version at whatever you chose.
  5. You should notice your connection is immediately more satisfactory if your data connection was better prior to the 4.4.1/2 update.
Extending Your Battery Life
This Fix Works For
  • People’s who’s devices are draining power in standby.
  • People who generally want their device to function longer.
  • People who need their device to work for a full day. *not all active use*
  • Basically everyone, it’s just a quality of life tweak.
  1. First things first, Wifi

    1. Go into Settings, Wifi
      1. Click on the three dots in the bottom right hand corner.
      2. Click advanced.
      3. Now un-check scanning always available, set keep Wifi on during sleep to always or only when plugged in to save even more, and turn on the Wifi optimization.
  2. Now lets go to Location Settings
    1. Again Settings, Location
      1. Click on the mode at set it to high accuracy. *for some reason I get better battery life with this setting then any of the others, weird.*
  3. Go to the Play Market and download This Application. *requires root, again see above on how to get root*
    1. Use this app to Greenify applications like Facebook twitter etc that you don’t need sucking your battery or getting your device wake-locked constantly.


Nexus 5 - Android and Radio Verison Nexus 5 - Battery Life

So guys that’s everything, if you have any questions. NOT REGARDING THE DRIVER INSTALLATION please feel free to e-mail me also feel free to repost this anywhere you see fit as long as you give credit to me :).
Hope this can help at least some of you guys out, sorry about the grammar and formatting it’s late and I’m kind of rambling and pushing to get this done.
34 Comments Post a comment
  1. Babs #

    My problem is that the Nexus 5 doesn’t get any mobile network whatsoever, regardless of reboot, factory reset, clearing cache etc so I have no cellular service whatsoever.
    Would trying this fix it?

    February 4, 2014
    • Do you have your APN settings correct for your carrier? Go verify that your APN settings are correct for your carrier first and then go ask for a replacement SIM. If neither of those things work I recommend you RMA your phone through Google or ask your provider for a refund. That’s not a problem that these fixes will fix most likely.

      February 4, 2014
      • aviad #

        hey there,
        i have the same problem as this guy. i tried another sim and it didnt work. i cant ask for google to replace the phone because im out of the US.

        if ill try to flash my modem again can it work?
        i tried installing a different rom and it didnt help.

        August 19, 2015
      • Avaid,

        You can go ahead and try to flash the modem of the phone if you want to give that a shot. The problem with not connecting to a cellular network at all can sometimes be due to what band of cellular signal you’re phone is trying to connect to you need to find out if your carrier is providing the right frequency of signal for the phone. I’m not sure what country you’re in but you should check around and see if the Nexus 5 supports the bands that your carrier is on it may or may not.

        September 8, 2015
  2. Paul #

    So, I followed the steps for the Fast Dormancy disabling and flashing the modems.
    Flashed the whole list of modems one at a time. Using the Open SIgnal app, my signal was at ~ 32% when right next to my femtocell box (my wife’s HTC One was at 90%). 2 of the modems got me up to ~ 60% signal. Still not great for being next to the box, but better then it was certainly.
    Ended up using the KRT16M modem.

    Haven’t tried out in the real world, yet to see if that translates to better service or not.
    Thanks for all your work and the tutorial – very easy to follow

    Hopefully, Google will get on this soon

    February 6, 2014
    • Paul,

      Great to hear that someone else out there got some use out of this. I agree hopefully Google will get on this soon too it’s rather simple and o wonder why it’s taking their engineers so long to publish an official update :/. I’ve noticed better overall results with the phone regarding battery life and standby time without fast dormancy and a new radio too.

      February 6, 2014
  3. Same problem as everyone else. Got another phone from google rma . Ran both phones simultaneously and both had same problems tried every combination of of 2g 3G 4g without success. Unable to regularly make receive call or send text messages plus keep getting annoying emergency calls only screen. Tried factory resets, updating software, everything recommended on line bar rooting as is still within warranty.
    At one point I had 2x nexus 5 and my old galaxy s3 running all on Vodafone uk. Results were nexus time without signal 30-40% galaxy s3 time no signal 4-10%. Have screen grabs as evidence and took readings for a week trying to solve issue without success. Time to send nexus back and get a phone which works without resetting or airplane mode switch. Losing business as result of missing calls & tired of carrying two phones around with me – Vodafone contract and payg (nexus diverting to s3 when no signal) The most annoying thing is having two bars of signal showing and still being unable to make calls. See my youtube videos search nexus 5 connection issues/problems.
    REALLY REALLY WANTED THIS PHONE TO WORK as upgraded wifi router for ac, phone cases & screen protectors thankfully was able to send back wireless charger. Hope google will admit problem or produce a fix or I fear my credit card company will be fighting for my money back for a product which is not fit for purpose.

    February 8, 2014
  4. Good Afternoon Paul,

    The first thing I’d like to do is to say “Kudos to you” for willingly and clearly assisting others at no charge. You don’t even ask for a “LIKE” of any kind. Both are very unusual in this day and age.

    I found your article EXTREMELY interesting and enlightening. The instructions you posted were for a Nexus 5. I’m having the EXACT same issues with my Samsung Galaxy S3 i747.

    I’m wondering if you might be aware of an article such as yours that is particular to Samsung in general or specifically to the i747 in particular.

    Thank you in advance for your time.

    Frank Koniszewski

    February 19, 2014
  5. Dan Shaw #

    The image for fast dormancy is not there. Has there been a change to the instructions?

    February 23, 2014
  6. Anyone know what the fast dormancy commands are? Thanks!

    February 25, 2014
  7. Sly #

    Hi Ian,

    Thanks for the fix and further tips. Like an awful lot of users out there, I’m getting disconnected from the cell network about once a day, that only a reboot can sort out.

    However, I can’t see any difference with the “” line in /system/build.prop and still get disconnected like nothing ever changed. Would you by chance know of a way to check the fast dormancy status or activity, via “adb logcat” or any other mean? Just so I can double-check that I have indeed control on this infamous fast dormancy feature…

    In case this is of any interest, I’ve also tried adding a “,20815” line (the numbers being my local network PLMNs) but again that didn’t seem to change anything.

    On to checking other radio firmwares now. Thanks again for sharing your experience!


    March 4, 2014
  8. The build.prop command you posted seems to be helping out a lot with my signal. Previously, my signal would drop down and I would have “No Service” afterward even when it jumped back up to two or three bars!

    Now, things appear more stable. I still go down to no bars sometimes, but it no longer causes me to lose service entirely until I reboot. I’ve only been using it with the build.prop modification for a couple hours, though. I guess it could still throw me a curveball, but it already seems much more stable than it was before. Thanks for the guide!

    March 11, 2014
  9. James #

    Wow, thanks for the article! I have a nexus 5 that was not always performing efficiently when it came to signal and its effects on the battery. The article was very well written.

    I have one question though. It’s there any benefit from disabling fast dormancy if your carrier most likely sports it? I am on AT&T (through straight talk) and do not know whether or may actually be harmful to my battery.

    Thanks again!

    March 16, 2014
    • Disabling FD if your carrier supports it is generally a no no. This will cause all sorts of connection issues, battery life drain, and various other problems so be careful with that!

      March 17, 2014
  10. Penguin #

    Hey Ian,
    I’m stuck on part 4.ii in “How to Get Better Signal Overall”.
    My Nexus responds to everything I tell it to do in the toolkit except for the ‘Reboot Bootloader’ function.
    My phone just sits there doing nothing while my PC is trying to get it to reboot.
    I tried everything i could think of, without success.

    Any help would be greatly appreciated!

    March 26, 2014
    • Penguin,

      You might want to try to get the correct drivers installed? I’m assuming that’s going to be the issue. If you follow the step by step guide in the wugs kit then you should be able to figure it out. It’s a little finicky and different from every PC make sure you follow the instructions to a T.

      April 27, 2014
  11. Jasmin #

    Is there a tutorial like thisfor Nexus 4? Or is this applicable on Nexus 4? My Nexus 5 is working just fine, but on Nexus 4 I’m experiencing all these problems?

    April 27, 2014
    • Jasmin,

      Your Nexus 4 should respond to this guide very similarly. There might be a few differences but the fast-dormancy option can be disabled on the Nexus 4 as well.

      April 27, 2014
  12. Hi Ian, thank you very much for your input, just wondered if you knew a way to enable the “System Select” menu under mobile networks? I still find my device (despite updating, rooting, editing build.prop and your other suggestions) tends to land on a network which supports calls but not data; result no data and a very flakey performance.

    June 5, 2014
    • Steve,

      I’m wondering if you’re talking about the APN settings for your carrier? If you are it would be under wireless settings for your carrier just through the systems setting menu. Within that you can specify specific APNs for your provider. Outside of that there is a feature that when you type *#*#4636#*#* into the dialler app it will bring up a hidden field test menu. Within that you can change your phone to only pick up and connect to certain bands. Give both a go your mileage may vary but good luck!


      June 6, 2014
  13. At the end of this line –

    Do I need the comma at the end? I’m thinking no but want to be sure before I try this.
    Also, do I still need to try this if I’m running 4.4.3 or was this already addressed in this release? I personally am still having signal issues. The signal on my battery stats is mostly gray and yellow with slivers of green mixed in.

    June 13, 2014
    • Elbowduck,

      You don’t need to have the comma at the end of that line.


      June 25, 2014
  14. At the end of this line –

    Do I need the comma? I’m assuming no but want to be sure. Also, can I still try these changes if I’m on 4.3.3? My signal bar in my battery stats is always mostly grey and yellow/gold, with only little slivers of green here and there.

    June 13, 2014
    • Elbowduck,

      The changes can still be added on 4.3.3 I’m not sure if Android has changed the ability to modify this setting on 4.3.3 but I don’t believe it has.


      June 25, 2014
  15. Miguel #

    F$%k! So I changed the build.prop and copied and pasted your line onto its separate line under Extra Build Qualities. I rebooted and it showed the Google logo, the logo disappears and all I see is a blank screen.

    Did I put it in the wrong place or the wrong section? I followed your directions exactly. You need to put a photo so people don’t do these things. Now how do I get myself out of this mess? I just spent the last 24 hours resetting my phone and installing everything. Now I’m dreading having to install everything again from scratch.

    June 19, 2014
  16. Nayan #

    No need to root. I found an easy way for my Nexus 5.
    Dial *#*#4636#*#*
    And select the network WCDMA only. It works 🙂

    September 15, 2014
    • ali #

      Thanks a lot! Finally this solved 3g connectivity issus after updating my nx4 to 5.0.1 lollipop.

      December 24, 2014
  17. luis #

    Yeha Nayan. U r the one. It’s works so well thanks man.

    December 22, 2014
  18. Seth #

    My problem is on att at home i only have edge service and it randomly disconnects the fast dormancy fix made it work better at home but when i went into the city were they have lte coverage thinks did work right with fast dormancy off

    December 27, 2014
  19. Great work

    February 1, 2015
  20. Hairum #

    Hello i have problem with my motorola droid razr M that it cellular signal always poor and sometime there is no signal.A few month ago no problem with my phone signal.My wife use same phone model like me but until now his signal phone is better than me.Only one thing that i confuse that my wife phone use android 4.4.2(kitkat) system version 182.46.15 and my phone use android 4.4.2(kitkat) system version 183.46.15 forum that i read in the internet talk about android 4.4.2(kitkat) system version 183.46.15 have a signal issue.Can it fix same way guide that you give above?Or other suggestion?Please i want your help.

    February 9, 2015
  21. William Ramirez #

    Thanks, My nexus 5 was dropping signal both LTE and cellular about every minute or two. I went down the list on the radios and tried all of them until I got to the one you recommended. D820 KRT01B (4.4) That seemed to do the trick. It’s been 1 hour with no disconnects.

    June 22, 2015
    • Marshall #

      hi everybody.
      I have a Nexus 5 running 6.0.1 it was working fine except for the battery which was draining fast.
      yesterday my phone showed the “emergency calls only” message.
      I typed *#*#4636#*#* and selected several network types but nothing helped.
      sometimes my phone catches 2G network but no available cellular data and can’t make calls or receive messages.
      please help me.

      April 5, 2016

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