[Radio] Enable LTE Band 3 and 8 on D820 and LTE Band 2 and 4 on D821

Guiper

Senior Member
Sep 9, 2008
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Hi,

Credits to the user Azlun who initially posted the solution on the gfan foruns (In chinese).
I'm just creating a thread here in xda to raise attention for more developers and other people which might be interested.

Azlun managed to enable some extra bands in the Nexus 5 phones. Since a lot of people import the phones, relocate or travel, this can be useful for people.

I'm not responsible if you burn your phone or make a brick from it. It has been confirmed to work for a couple of users without any downsides.

Before making any changes, please make sure you do an EFS Backup (preferentially using TWRP) as well as a backup of your original NV in a qcn format details using the QPST software download tool (instructions bellow).
This hack will be maintained even if you flash any roms or OTAs, unless you restore your EFS partition from a backup or the original qcn via the QPST software download tool.

User Xtachix put together the basis for this tutorial! Thanks! (Still under development)
Prerequisites:

First thing is first, you will need to download the file available (Will update later today).


Walkthrough/guide for adding Band 3 and 8 to D820 and 2 and 4 to the D821. Make sure you select the correct file.
Don't cross flash, as we don't know what might happen!

  • Preparation Windows
    • Install the LG Diag Drivers executing the file lg_android_31010.exe
    • Install the QPST tool, QPST_2.7.411
    • QXDM is optional and used to debug / confirm the mod has been done.
  • Preparation Nexus 5
    • Install the app Nexus 5 Field Test mode
    • Make sure you have the phone rooted
    • Enable usb debugging
    • Now you need to obtain your SPC code. For doing it open Nexus 5 Field Test Mode App, got to settings (view), then LTE, and click on edit. At the same time use logcat to get the SPC code
      Code:
      adb shell
      logcat -d | grep "commandId\ 200"
      You should get something like
      D/LG_SVC_ITEMS(18638): getCommands commandId 200 = ******-END
      Where the "*" values are the digits to your SPC.
      NOTE YOUR SPC CODE DOWN!!
    • Now let's make sure that your NV becomes writable, go back into the Field Test Application, input the SPC code from above, and make sure the settings look like the picture bellow. Important is to disable band 26 and set priority of 41 to 0. (Don't worry band 26 will become available again after flashing the qcn).
    • After setting it, click back and your phone will reboot. This is expected
    • Make sure the kernel you are using supports DIAG mode. If you are not sure, reboot your phone into bootloader mode and boot using fastboot this kernel (even though it says 4.4.2, it will work for 4.4.4).
      Code:
      fastboot boot 4.4.2_diag_BOOT.img
    • Reboot phone into the ROM and keep it connected to the computer.
  • Executing the hack
    • Now you have to use ADB through a pc, to get you phone into DIAG mode
      Code:
      adb shell
      su
      setprop sys.usb.config diag,adb
      your device will disconnect and reconnect to become a COM port device. that's what you want.
    • Open device manager and check the COM port of the nexus, note it down.
    • Open your recently installed QPST software in windows. Windows 7/8/8.1 make sure you execute it as admin!
    • Select the ports tab and add a new port. the COM port that you noted down is what you want to select on this window. Click ok.
    • Now you will be back at the "ports" tab with your nexus 5 COM port. Up in the menus select "Start Clients" and select Software Download.
    • To be safe let's do a backup. Select the backup tab and perform a backup of your initial NV status to any file in a safe location on your computer. It may take around 5 minutes to perform the full backup.
    • Select the Restore tab.
      Now select the correct QCN file, attached on this post.
      • D820_RF_LTE_ENABLE_B3_B8_RemovedSameItem_NOT_Overrided.qcn - Adds LTE band 3 and 8 to the D820. (Band 8 not tested, let us know if it works)
      • D821_RF_LTE_ENABLE_B2_B4_Filtered_RemovedSameItem_NOT Overrided.qcn- Adds LTE bands 2 and 4 to the D821. (Band 4 not tested, let us know if it works). File updated due to a minor typo.
      for your SPC code, use what you have obtained above.
      Allow phone/file ESN mismatch" has to be ticked.
    • Click Start. After a few seconds you will see and Error .
      Errors: Could not Reset the Phone. Communication Errors Occurred. Do not panic, this means you did everything correctly :)
    • Reboot your phone.

    You should the extra bands working. Let us know if works, since we are still experimenting. We are specially looking for feedback on bands 4 for the D821 and band 8 for D820.

    There is no easy way to confirm if the new bands are working or not without connecting to them.
    Using QXDM tool you can confirm the mod has been applied, but if you are not in an area with LTE you cannot confirm it works.
    Some debug steps is to make sure your Preferred Network mode is selected as "LTE (recommended)" and your SIM Card has 4G enabled.

To disable the hack, just restore the original EFS (preferentially)and/or the qcn backup.



For more details take a look at the service manuals available here. Interesting sections are 3.5 and section 5 the RF Block.

Keep in mind that we can't enable extra bands which are not available in any of the version of the phones.
Also D820 cannot work on B20 (HW is different), neither B7 (HW is not there at all).
 

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Guiper

Senior Member
Sep 9, 2008
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DigitalJosee

Senior Member
Mar 1, 2013
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Seems Nexus 5 have a max. number of enable LTE bands active at the same time, disabled 26 and actived 7, using fffft's method and vndnguyen's calculator.

THANK YOU GUYS!
 

meher91

Senior Member
Jan 15, 2013
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Hyderabad
Seems Nexus 5 have a max. number of enable LTE bands active at the same time, disabled 26 and actived 7, using fffft's method and vndnguyen's calculator.

THANK YOU GUYS!
Hey I'm trying to do this type of Mod for the first time on my phone...So forgive me if I ask something stupid...
I have a few doubts about the steps mentioned in fffft's post:
Step 3 - Is Custom ROM really necessary for Nexus 5?
Step 6 - I cant find the USB settings menu using any of the codes mentioned...
For the moment i'm stuck here...

Can you please solve my queries & If you dont mind can you post some details about Nexus 5 specific changes to be made to the method mentioned in fffft's post
 
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M.Noury

Senior Member
Oct 19, 2007
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Jeddah
Hey I'm trying to do this type of Mod for the first time on my phone...So forgive me if I ask something stupid...
I have a few doubts about the steps mentioned in fffft's post:
Step 3 - Is Custom ROM really necessary for Nexus 5?
Step 6 - I cant find the USB settings menu using any of the codes mentioned...
For the moment i'm stuck here...

Can you please solve my queries & If you dont mind can you post some details about Nexus 5 specific changes to be made to the method mentioned in fffft's post
If you want to enable LTE band 3 only, you don't need custom ROM/Kernal. You will only need Root.

Sent from my Nexus 5 using Tapatalk
 

amritpal2489

Senior Member
Oct 3, 2010
304
45
48
Hey I'm trying to do this type of Mod for the first time on my phone...So forgive me if I ask something stupid...
I have a few doubts about the steps mentioned in fffft's post:
Step 3 - Is Custom ROM really necessary for Nexus 5?
Step 6 - I cant find the USB settings menu using any of the codes mentioned...
For the moment i'm stuck here...

Can you please solve my queries & If you dont mind can you post some details about Nexus 5 specific changes to be made to the method mentioned in fffft's post
I am also finding a way to open USB settings menu. Can anybody help us out with that?
 

DubelBoom

Senior Member
Jan 10, 2011
1,805
311
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If anyone founds a way to edit the QCN file please share with us. I want to replace the NV Items there to support the bands I need, but QCNView won't allow editing..
 
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Guiper

Senior Member
Sep 9, 2008
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Hey I'm trying to do this type of Mod for the first time on my phone...So forgive me if I ask something stupid...
I have a few doubts about the steps mentioned in fffft's post:
Step 3 - Is Custom ROM really necessary for Nexus 5?
Step 6 - I cant find the USB settings menu using any of the codes mentioned...
For the moment i'm stuck here...

Can you please solve my queries & If you dont mind can you post some details about Nexus 5 specific changes to be made to the method mentioned in fffft's post
DId a minor update to the steps. Still it's not straightforward and will require some reading, but at least it's better!
 

silentdoh

Member
Jun 14, 2012
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Would it be possible to use a method similar to this to enable Band 12? The new T-Mobile deployment on it is making the N6 look pretty nice, even with the giant size and price tag.
 

Azlun

Senior Member
May 9, 2013
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Shenzhen
Thank you to post my Sept 20th gfan post http://bbs.gfan.com/android-7648826-1-1.html
band3 enablement here.
To edit qcn,
Who can find QRCT from Qualcomm; just use QRCT-TOOLS-NV Manager,1st Save qcn as xml and edit it in text,
Then save it with QRCT-TOOLS-NV Manager again to qcn.
For who can not find it, I have no idea.
Sent from my SM-G9006V using XDA Free mobile app
 
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cornholio_rules

Senior Member
Dec 29, 2010
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Thank you to post my gfan post band3 enablement here. To edit qcn,you need qrct-nv tools,to save qcn as xml and edit it in text,then save it with qrct again to qcn.

Sent from my SM-G9006V using XDA Free mobile app
Great job Azlun, could you make a qcn file for D821 with added 2/4 LTE bands please? :)
 

Azlun

Senior Member
May 9, 2013
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Shenzhen
Qcn for D821 to enable Band 2 and band 4 for North America Opeartors

Great job Azlun, could you make a qcn file for D821 with added 2/4 LTE bands please? :)
Here attached the qcn for band2 and band4 enablement, my NEXUS5 D821 is not in hand, so not test yet.
you can just try and let us know the results.
ATTENTION:
before below steps, use TWRP to backup your EFS 6MB file can copy it to your PC safe space, also, use QPST-Software Download-Backup tab to save a qcn file for value restoring, Please note EFS 6MB is more batter than backuped qcn. both these you should do in order to further fallback when you lost your direction.
Trail 1. User QPST-Software Download-Restore Try:
Fail solution\D821_RF_LTE_B2_B4_NV8628_NV6829_Set.qcn,
Trail2. touch back key in NEXUS5 Field Test Mode-Setting-LTE-Edit-input correct SPC as POST#1 here, then NEXUS5 will give you a button to restart and checked your LTE is working or not with LTE Discovery-EARFCN-Check
I am 99% sure it will FAIL since this old method do not patch on NV24227,NV24229;
Trial3. Do Trial1,Trial2 with My recommend qcn:
recommand\D821_RF_LTE_B2_B4_Filtered_RemovedSameItem_NOT Overrided.qcn
Trial4. if Trial3 fail to make you found the LTE, Do Trial1,Trial2 with Then restart your phone using
2nd solution\D821_RF_LTE_B2_B4_Filtered_RemovedSameItem_Overrided.qcn
Trial5. if Trial4 fail to make you found the LTE, Do Trial1,Trial2 with Then restart your phone using
2nd solution\D821_RF_LTE_B2_B4_Filtered_AllItems_Overrided.qcn
NOTE: the later solution you used, the more NV Items you have been overrided, that is bringing your RF Front end go further from factory settings. each xml files inside my attachment is telling you what Items you are modifying, you can compare.
Please note that NOT all the bands can be enabled in this way, the limitation is the Hardware Radio Frequency Front End components design in the Service manual page 203.
 
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Azlun

Senior Member
May 9, 2013
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Shenzhen
So will it be possible to covert a D820 to D821 or vise versa?

Sent from my Nexus 5 using XDA Free mobile app
NO, you can not, since D821 removed band41 Radio Frequency Front End components Filters and Power Amplifier Module,
Another side, D820 removed band 7 Radio Frequency Front End components, even they both using one PCB with difference reserved space for different bands.
if you are a expert on PCB soldering, you can add it back to PCB, then use my qcn to patch it depand on your device name.

---------- Post added at 03:30 PM ---------- Previous post was at 03:24 PM ----------

Seems Nexus 5 have a max. number of enable LTE bands active at the same time, disabled 26 and actived 7, using fffft's method and vndnguyen's calculator.

THANK YOU GUYS!
band 7 is cut in Hardware in D820 according service manual PCB pictures vs D821. so only PCB soldering expert can find a solution.
document is here:
http://forum.xda-developers.com/google-nexus-5/general/service-manual-d821-t2791303
and I have some explanation in Chinese here:
http://bbs.gfan.com/android-7664034-1-1.html

---------- Post added at 03:44 PM ---------- Previous post was at 03:30 PM ----------

Please note that wiki page just only list all official documented for China, I tried to persuade the admin to update band 1 and band 3 info for China Telecom, and band 3 info for China Unicom, but fail.
THE Fact is Band 3 is widely used for national coverage over 44 cities by both Operators above in a commercial purpose.
and band1 is used by China Telecom for some area Outdoor and some shopping mall indoor coverage.
the government documents will tell you those are trial networks, but the fact is all 4G USIM cards from CT and CU is major using such network for 4G user service,
Another side, Band41 is official assigned to All China Mobile, China Telecom and China Unicom for also 1 year, but all of these operator do NOT use it for widely coverage outdoor, the most investment is from China Mobile, only some down-town new base stations or new deployment area are using band41. it is not a full coverage network, and network based Fast Return to band41 seems still have problem in current China Mobile networks. Further info, China Mobile major 4G networks is band39 for Outdoor and band40 for indoor.
 
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