[Nexus 5 Q&A, Help & Troubleshooting] hendrali:
This is just a small guide on how to flash Nexus 5 D820 (US version) from Sprint to other CDMA carriers. Please mind that this is a trial and error guide which I tried many times before I succeeded flashing my Nexus 5. So if there are some mistakes that needed to be corrected , please tell me and I won't mind :).

So let's begin: First, you need to root your Nexus 5. I will not provide on how to root it since there are lots of guides out there if you google it. Ok, after that you need to install the Nexus 5 Windows driver which you can download it from here: http://drivers.softpedia.com/get/MOBILES/LG/LG-United-Mobile-Driver-381.shtml

Since LG Nexus 5 doesn't have dial code for diag mode we have to flash diag mode boot img file which you can download from here: http://xdaforums.com/attachment.php?attachmentid=2421929&d=1385715923

You can use Flashify which can be downloaded from Google Play Store to flash the img file. The phone will reboot after you flash it.

Ok, after all that you can connect the Nexus 5 to the pc/notebook using the usb data cable. Usually Windows will automatically install all the drivers for the Nexus 5 once you connect it. Oh, don't forget to enable the USB debugging mode from the developer options menu.

After all the needed drivers have been installed, we will enter the rather complicated on how to use adb shell command. You all can read the guides here: http://xdaforums.com/showthread.php?t=2514396

There will be SDK Tools which you have to download for Windows. The guide will tell you all on how to install it.

For the flashing tools, we need:

1) CDMA Workshop 3.9

2) DFS tools

3) QPST

All these tools you have to find/buy them by your own since I can't provide them. Sorry. :)

Ok let's enter into diag mode. Go into command prompt window and type:

adb shell

then type:

su

(here the $ sign will change into #)

and then type:

setprop sys.usb.config diag,adb

Ok we should be in diag mode now. We will use CDMA workshop first. Set the port. and then click connect. We will find the SPC code and change it. Go into the security tab. In SPC/user lock , let's change the Default (NV_read) into LG method. and click read. We will see some numbers in the box. We will click the SPC button now, there will be a writing like this: Write "000000". Choose that. And SPC code has been changed from those confusing numbers into simple numbers 000000. We succeeded unlocking the SPC. Click reset on the right top corner (it looks like reload button). After that reboot your Nexus 5.

Get into diag mode again. Open your CDMA Workshop again. Connect. Get into memory tab. Go into NV-items. Write nv-item which you can download from: http://www.cricketusers.com/sprint-lg-optimus-s/16145-optimus-s-cdma-ws-3-x-nv-items.html

Ok choose reset and then reboot your phone again.

Get into diag mode again as usual. We will use DFS software now. Choose port. Connect. And click SPC which usually written down 000000. It will unlock the phone so we can write down settings into it. All right in here go to Programming tab where you need to enter all your MDN, MIN, Akey, PRL, etc informations which you can get from your own carriers/operators. If using DFS is confusing, please read the guide first. I am sure you can find some in google :).

Ok if everything is written and you press reset on DFS. Reboot your phone. Usually after this you can use your phone for calling and sending SMS text. Oh, don't forget to insert a simcard in your phone. Usually just put a GSM card. This phone can be used for either CDMA or GSM. There will be a new menu in mobile network. LTE-3G-1x-Global(GSM).

But the 3G EVDO for data connection will not work at this stage. So we will use QPST software. Use the latest QPST software 2.7 built. Connect and as usual you have to enter SPC code. Go into PPP config tab. There you will go into Um tab. Check if our user id is the same as the user id as given by your own carrier or is it still filled by Sprint's user id? If the Sprint's id is still written there, go into the user id box and press ctrl-d from your keyboard to wipe the Sprint's ID. And then do the same thing in AN tab. After all that, press write to phone. Reboot your Nexus 5.

Get into the diag mode again...hope you guys don't get tired of it though :laugh: Open QPST, read from your phone, get into PPP config. Go into Um tab and the user id box should be empty now. Fill it with your user id and password too. And do the same thing in AN tab. Go into M.IP tab and check if profile 1 (ignore profile 0) is enable. get into it and check if both NAI and Tethered NAI are written with our own user id. Write to phone and reboot your phone.

We will wait for a few minutes......and usually 3G EVDO sign will come up. Go into About Phone, take a look in Status is it written: CDMA-Evdo rev. A....if it is congrats, you have successfully flash your phone with your own carrier. :laugh:

Hopefully this guide will help you guys. I know it's a bit confusing. Hey it's my first time writing a guide....If there's any mistake that I made, please don't hesitate to tell me. Thanks guys.