[TUTORIAL][Radio] Enable NEXUS6 XT1103 4G LTE B1/B8/B9/B19 and also XT1100 B2/B4

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Azlun

Senior Member
May 9, 2013
340
217
Shenzhen
As I brought Band3 for NEXUS5, here, we are bringing 4G LTE band1 IMT 2100MHz for users such as, but
not limited to:
China Telecom,
Japan AU/NTT Docomo/Softbank,
Korea LG U+ /SK Telecom,
Philippines Smart,
Thailand DTAC/TrueMove-H
according http://en.wikipedia.org/wiki/List_of_LTE_networks#Asia and more:
Czech Republic Vodafone
Poland Play/P4
according http://en.wikipedia.org/wiki/List_of_LTE_networks#Europe

20150412 UPDATE: we are in Trial of more bands,as attachment names at POST#33:
Band 2 and band 4 for XT1100 View attachment 3257101
and Band 1 and band 8 or Band 1/9/19 or Band 1/8/9/19 for XT1103 View attachment 3257100


I am sorry below English language is not good, it is come from Google Translation^_^ from my Chinese post.
attachment docx is more clear since more detail images can are attched inside:
EN:View attachment 3187257
CN:View attachment 3187214

NEXUS 6 US MOTO XT1103 Band1 Enablement Tutorials
Foreword:
With the US version NEXUS6 XT1103 Chinese users, most of them come for China Telecom
, but is there such a telecommunications in many indoor shopping centers and car parks, do 4G LTE band1 2100MHz coverage, but also greater bandwidth than band3 15MHz with 20MHz bandwidth with China Telecom license.
What is a pity, XT1103 band1 RF front-end is shipped out without factory calibration, so only official usage is 15MHz@band3 only for China Telecom.In fact, as NEXUS5 band3 enablement, NEXUS6 RF front-end hardware also left a tiny space to enable it. The following tutorial is the first edition, With more extensive testing,It will needs correction on your demands.
I am sorry I do not have English version computer to reworks the Chinese screen captures,
I believe you have some way to understand around.​

STEP1: using TWRP backup EFS
you can nexus6 of TWRP-Backup-EFS. More insurance after the phone Root, you canalso EFS Professional to backup your original EFS.
Thus, When need to restore the original state , Just use TWRP-Restore- to select the original EFS and slide the button to restore any changed below.

STEP2: Install the driver Moto BP Tools Driver
Mobile side: the phone off, then press the power button + volume down key, enter fastboot mode, use the volume keys to select BP Tools, and then turn the power button to confirm. Open usb diag device port.
1.0.pngView attachment 3187207 View attachment 3187208


1. Connect your phone to your computer, then prompted to install "diag_mdm" drive (or right-click "My Computer" and select "Properties" - "Device Manager" to install "diag_mdm" drive)

2. Right-click on the "diag_mdm", select "Update Driver Software" and then select "Browse my computer for driver software."


3. Select "choose from a list of device drivers in your computer."

4. Select "Show all devices", the "Next" button.

5. select "Disk"

6. Click "Browse"

7. Select the folder where you drive, point to open after selecting "momdm", then OK.


8. Select the "Motorola USB Diagnostic Port", click "Next."

9, warning, Click "Yes"

10, in the Device Manager port as shown below to show that the installation was successful (Note: The port number com93 vary)
1.a.png

STEP3: Write qcn
Phone side: the phone off, then press the power button + volume button, enter fastboot mode, use the volume keys to select BP Tools, and then turn the power button to confirm, so you can open the usb diag device port.
1.the installation QPST. Do not use lower version 2.7 build 422, otherwise it will not recognize the device. please find such installation by yourself.
2. open QPST configuration, the first point of Ports tab, select the device displayed, the first point below "remove", Prompt window popuped, and then point "Yes".

3, Chick "Add New Port".

4. Select the port of your device com port, and then "OK" button.

5, open the folder points QPST Software Download, click on "Restore" tab, click Browse to select the desired brush into qcn file:
View attachment XT1100_LTE_B1_To_XT1103_24226_6735_6736_RxAdded_TxOverrided.qcn.zip
(Here, the only difference vs nexus5 enabled band3 ,XT1103 purchased from Google Play, MOTO did not change default SPC, 000000),
Check Allow phone / file ESN mismatch, the final blow: Point Start, Errors box appears Could not Reset the Phone error normal, qcn has finished writing, after using the Power button off, then boot directly out LTE signal, the restart, do not use QuickBoot like Reboot, to ensure safety.
2.5.png2.5+.png

FINALLY: Check Whether Band1 Enablement successful methods
Method 1: Insert China telecom USIM cards, confirming a place where band1 with LTE Cell ID can be found with the end of HEX is 00,01,02,03,04,05 of LTE base stations (in the dial-up interface, enter * # * # 4636 # * # *, open "mobile phone information ", the" Set preferred network type "to LET ONLY, and then find the" Location: LAC = 7101 CID = 1924c01 "in this column, the CELL ID is inside this CID.
3.1.png
Method 2: Use the LTE Discovery watch band states.
NOTE: These two methods are there GCI (CID) guessing band, is only applicable to some of operators such as China Telecom, the absence of good planning China Unicom 4G CellID, and also China Mobile is not applicable for this .
NOW@201504, we have LTE Discovery update to 3.19, support NEXUS6 display the real MODEM LTE Band!! thanks for Danial and his great team!!
3.2.jpg Screenshot_2015-05-06-20-30-42.jpg Screenshot_2015-05-04-19-58-13.png Screenshot_2015-05-05-19-41-47.png
While you want to Check real band PC tool QXDM may help if you have such tool, menu path is View-LTE- RRC layer-RRC/NAS Status Screen- Frequency band, wait for 10mintues for update or use airplane mode on/off to Tigger update.
In case you are not in LTE covered area, but just want to check the qcn is applied or not, reset your phone in boot loader mode, select BP TOOLS again,them use QXDM-view-NV Browser-Item 06828- read to get the value, it should be 1099830466655 for add band1 while stock default is 1099830466654,
Other qcn XT1103 add:
B1/8 1099830466783
B1/9/19 1099830729055
B1/8/9/19 1099830729183
XT1100 add:
B2/4 1099646632415, @default 1099646632405

Here we must thank:
Q39705630 enthusiastic and efficient testing and Draft this tutorial V0.1 version;
Q562552826 provide XT1103 of qcn file, doing preliminary analysis;
Q386499038 provide XT1100 qcn file, do the final release qcn file parameter reference;​

Other Reference Tutorial IN Chinese:


1. CN version band1 enablement:
http://bbs.gfan.com/android-7863761-1-1.html
2.NEXUS6 RF parameters such as PC-side backup method qcn
http://bbs.gfan.com/android-7741730-1-1.html
3. Some tools on LTE band1 signal monitoring
http://bbs.gfan.com/android-7684876-1-1.html
 
Last edited:

MaxChuang

Member
Feb 17, 2015
6
0
Could you send the xt1100'qcn to me? Q2954103426 . If I retore xt1100's qcn to xt1103, it only can make xt1103 support band same as xt1100?
 

messedupqcn

Member
Mar 1, 2015
5
1
Hi, I messed up my NV values and I can't get signal anymore. Can you please post original XT1103 QCN file so we can restore the backup? Thanks. :eek:
 
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Azlun

Senior Member
May 9, 2013
340
217
Shenzhen
Could you send the xt1100'qcn to me? Q2954103426 . If I retore xt1100's qcn to xt1103, it only can make xt1103 support band same as xt1100?

No, you can not enable all the band but some, and it need some technical filtering job,
RF front end hardware is arm and body of RF driver software soul.
I will try to bring band8, but need more weeks to find time gap during my work.
 

Azlun

Senior Member
May 9, 2013
340
217
Shenzhen
Hi, I messed up my NV values and I can't get signal anymore. Can you please post original XT1103 QCN file so we can restore the backup? Thanks. :eek:
Please note the normal QPST-Software Download backup qcn will not works for restoring,
and older QPST-RF NV Item manager backuped Qcn can not cover all RF nv now, so it is also not good choice for you to restore Solutions for your issue,
Soution1. In case you only lost your signal after you use 4636-Phone Info-Select UMTS band- US band, Try to set NV00441 to 0xFFFF with this qcn, by QPST-Software Download, an old post is here:
http://xdaforums.com/nexus-6/help/help-locked-nexus-to-usa-band-t2975290/page2
Solution2. for others failture reason, To NEXUS6 reflash the factory images will help to reset all your nv from backup eMMC partition,
How to is here: http://xdaforums.com/nexus-6/general/guide-flash-factory-images-nexus-6shamu-t2954008
 

mimsiroll

Senior Member
Dec 14, 2011
207
54
manila
Just wondering though, the com should be com93? Ir it could be any digit? Because i got com25 and i still insist it im flashing..it worked but it cannot tell the band im using that should be band 1.
 

MaxChuang

Member
Feb 17, 2015
6
0
No, you can not enable all the band but some, and it need some technical filtering job,
RF front end hardware is arm and body of RF driver software soul.
I will try to bring band8, but need more weeks to find time gap during my work.

Thanks for your contribution ! :)
I am curious if carrier aggregation can be configured ,too.
 

messedupqcn

Member
Mar 1, 2015
5
1
Please note the normal QPST-Software Download backup qcn will not works for restoring,
and older QPST-RF NV Item manager backuped Qcn can not cover all RF nv now, so it is also not good choice for you to restore Solutions for your issue,
Soution1. In case you only lost your signal after you use 4636-Phone Info-Select UMTS band- US band, Try to set NV00441 to 0xFFFF with this qcn, by QPST-Software Download, an old post is here:
http://xdaforums.com/nexus-6/help/help-locked-nexus-to-usa-band-t2975290/page2
Solution2. for others failture reason, To NEXUS6 reflash the factory images will help to reset all your nv from backup eMMC partition,
How to is here: http://xdaforums.com/nexus-6/general/guide-flash-factory-images-nexus-6shamu-t2954008
Thanks! Is fastboot flash radio enough to restore everything to normal? :laugh:

edit: looks like you have to reflash everything. Oh well.

---------- Post added at 06:28 AM ---------- Previous post was at 06:14 AM ----------

I restored the factory image and it's fine. There's a bug with the current factory image where it doesn't flash system and userdata when you run flash-all.sh, but it seems to have flashed the nv value backup without that. I didn't reflash system and userdata manually so I get to keep my phone without wiping.

Any idea why line 6828 in NV browser says 268501086 in my XT1103? According to LTE band calculator, this means the phone supports band 2/3/4/5/7/17/29. But Google Play says the phone supports 2/3/4/5/7/12/13/17/25/26/29/41. Any idea why this supports seemingly less bands?

Looks like some Moto X have this band configuration, but my Nexus 6 shouldn't. Can someone confirm their stock line 6828?
 
Last edited:

Biggster

Member
Nov 5, 2013
14
1
  1. Will this change stick even after a firmware upgrade, say, after upgrading to Lollipop 5.1?
  2. Is this technique applicable to a D820 Nexus 5 as well?
 

Azlun

Senior Member
May 9, 2013
340
217
Shenzhen
Thanks! Is fastboot flash radio enough to restore everything to normal? :laugh:

edit: looks like you have to reflash everything. Oh well.

---------- Post added at 06:28 AM ---------- Previous post was at 06:14 AM ----------

I restored the factory image and it's fine. There's a bug with the current factory image where it doesn't flash system and userdata when you run flash-all.sh, but it seems to have flashed the nv value backup without that. I didn't reflash system and userdata manually so I get to keep my phone without wiping.

Any idea why line 6828 in NV browser says 268501086 in my XT1103? According to LTE band calculator, this means the phone supports band 2/3/4/5/7/17/29. But Google Play says the phone supports 2/3/4/5/7/12/13/17/25/26/29/41. Any idea why this supports seemingly less bands?

Looks like some Moto X have this band configuration, but my Nexus 6 shouldn't. Can someone confirm their stock line 6828?

1: Is fastboot flash radio enough to restore everything to normal?
Az:I never try, may be you can try when you have enough partition backuped.
2. for nv6828, the stock default is 1099830466654
and after my qcn written, it should be changed to 1099830466655 (add band1)
in fact there is many other nv added and overrided, so a EFS backup before qcn write in is suggested.
I can not understand why your value become an unknow one.

<!-- Add Band1 in LTE bands over XT1103
default 1099830466654 decially = binary:
00000000 00000000 00000001 00000000 00010011 00000001 00011000 01011110B
(band 41 29/26/25 17 13/12 7/5/4/3/2 )
= 1099830466655 decially = binary:
00000000 00000000 00000001 00000000 00010011 00000001 00011000 01011111B
(band 41 29/26/25 17 13/12 7/5/4/3/2/!1!)
** other referenece,
ONLY Band8 = 128
-->
<NvItem id="6828" subscriptionid="0" name="NV_LTE_BC_CONFIG_I" mapping="direct" encoding="dec" index="0">1099830466655,0</NvItem>
 
Last edited:

Azlun

Senior Member
May 9, 2013
340
217
Shenzhen
  1. Will this change stick even after a firmware upgrade, say, after upgrading to Lollipop 5.1?
  2. Is this technique applicable to a D820 Nexus 5 as well?

1 my NV items will be kept in EFS until a factory restore including erase EFS partition to trigger factory EFS restoring.
so OTA upgrade will be fine, but next factory image whole reflashing will erase nv items in this qcn.
That is MOTO design while LG NEXUS5 have not such issue.

2. NEXUS5 D820 can enabled band3 band8 in the same way if you are in track of http://xdaforums.com/google-nexus-5/general/radio-enable-lte-band-3-nexus-5-d820-t2928561
but qcn in that post will NOT bring CDMA+LTE 1xSRLTE dual-stanby working, it is still in LTE only mode.
why NEXUS6 support 1xSRLTE is come from facotry by default, DI4.0 new modem firmware and trigger by right carrier_policy.xml from m_bing.
 
Last edited:
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messedupqcn

Member
Mar 1, 2015
5
1
Hmm, I seem to remember my line 6828 was the same unknown value before I changed anything. Stock. Then when I flashed your qcn, it became the 1099830466655. I have no idea why my phone came with less bands stock. :confused: it is XT1103 Bought from moto US store. :confused::confused: no way to test it either, until I am out of the US :(
 

matkwok

Member
Jun 9, 2010
41
26
OnePlus 9 Pro
Solved.

Anyone know how to get the SPC/MSL code if it's not all zeros? My N6 is Amazon sprint version but I'm using it out of US.

Sent from my Nexus ⑥
 
Last edited:

wintoon

Member
Feb 17, 2010
10
0
XT1100 to XT1103?
Is it possible to convert an XT1100 to an XT1103? Is it a hardware thing?

I would like to enable band 2 and 4 in the XT1100, is that at all possible?

I have both an XT1103 (borrowed) and my own, an XT1100. Could I copy the NV values from the 1103 onto the 1100? Would it cause any damage to try?

I dont mind formatting, but I also don't want a brick.

Thanks,
Sam.
 

wintoon

Member
Feb 17, 2010
10
0
How could I enable LTE band 4? Really thats the only one I need to enable. Any help is much appreciated. I am more than willing to test as well.
 

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  • 36
    As I brought Band3 for NEXUS5, here, we are bringing 4G LTE band1 IMT 2100MHz for users such as, but
    not limited to:
    China Telecom,
    Japan AU/NTT Docomo/Softbank,
    Korea LG U+ /SK Telecom,
    Philippines Smart,
    Thailand DTAC/TrueMove-H
    according http://en.wikipedia.org/wiki/List_of_LTE_networks#Asia and more:
    Czech Republic Vodafone
    Poland Play/P4
    according http://en.wikipedia.org/wiki/List_of_LTE_networks#Europe

    20150412 UPDATE: we are in Trial of more bands,as attachment names at POST#33:
    Band 2 and band 4 for XT1100 View attachment 3257101
    and Band 1 and band 8 or Band 1/9/19 or Band 1/8/9/19 for XT1103 View attachment 3257100


    I am sorry below English language is not good, it is come from Google Translation^_^ from my Chinese post.
    attachment docx is more clear since more detail images can are attched inside:
    EN:View attachment 3187257
    CN:View attachment 3187214

    NEXUS 6 US MOTO XT1103 Band1 Enablement Tutorials
    Foreword:
    With the US version NEXUS6 XT1103 Chinese users, most of them come for China Telecom
    , but is there such a telecommunications in many indoor shopping centers and car parks, do 4G LTE band1 2100MHz coverage, but also greater bandwidth than band3 15MHz with 20MHz bandwidth with China Telecom license.
    What is a pity, XT1103 band1 RF front-end is shipped out without factory calibration, so only official usage is 15MHz@band3 only for China Telecom.In fact, as NEXUS5 band3 enablement, NEXUS6 RF front-end hardware also left a tiny space to enable it. The following tutorial is the first edition, With more extensive testing,It will needs correction on your demands.
    I am sorry I do not have English version computer to reworks the Chinese screen captures,
    I believe you have some way to understand around.​

    STEP1: using TWRP backup EFS
    you can nexus6 of TWRP-Backup-EFS. More insurance after the phone Root, you canalso EFS Professional to backup your original EFS.
    Thus, When need to restore the original state , Just use TWRP-Restore- to select the original EFS and slide the button to restore any changed below.

    STEP2: Install the driver Moto BP Tools Driver
    Mobile side: the phone off, then press the power button + volume down key, enter fastboot mode, use the volume keys to select BP Tools, and then turn the power button to confirm. Open usb diag device port.
    1.0.pngView attachment 3187207 View attachment 3187208


    1. Connect your phone to your computer, then prompted to install "diag_mdm" drive (or right-click "My Computer" and select "Properties" - "Device Manager" to install "diag_mdm" drive)

    2. Right-click on the "diag_mdm", select "Update Driver Software" and then select "Browse my computer for driver software."


    3. Select "choose from a list of device drivers in your computer."

    4. Select "Show all devices", the "Next" button.

    5. select "Disk"

    6. Click "Browse"

    7. Select the folder where you drive, point to open after selecting "momdm", then OK.


    8. Select the "Motorola USB Diagnostic Port", click "Next."

    9, warning, Click "Yes"

    10, in the Device Manager port as shown below to show that the installation was successful (Note: The port number com93 vary)
    1.a.png

    STEP3: Write qcn
    Phone side: the phone off, then press the power button + volume button, enter fastboot mode, use the volume keys to select BP Tools, and then turn the power button to confirm, so you can open the usb diag device port.
    1.the installation QPST. Do not use lower version 2.7 build 422, otherwise it will not recognize the device. please find such installation by yourself.
    2. open QPST configuration, the first point of Ports tab, select the device displayed, the first point below "remove", Prompt window popuped, and then point "Yes".

    3, Chick "Add New Port".

    4. Select the port of your device com port, and then "OK" button.

    5, open the folder points QPST Software Download, click on "Restore" tab, click Browse to select the desired brush into qcn file:
    View attachment XT1100_LTE_B1_To_XT1103_24226_6735_6736_RxAdded_TxOverrided.qcn.zip
    (Here, the only difference vs nexus5 enabled band3 ,XT1103 purchased from Google Play, MOTO did not change default SPC, 000000),
    Check Allow phone / file ESN mismatch, the final blow: Point Start, Errors box appears Could not Reset the Phone error normal, qcn has finished writing, after using the Power button off, then boot directly out LTE signal, the restart, do not use QuickBoot like Reboot, to ensure safety.
    2.5.png2.5+.png

    FINALLY: Check Whether Band1 Enablement successful methods
    Method 1: Insert China telecom USIM cards, confirming a place where band1 with LTE Cell ID can be found with the end of HEX is 00,01,02,03,04,05 of LTE base stations (in the dial-up interface, enter * # * # 4636 # * # *, open "mobile phone information ", the" Set preferred network type "to LET ONLY, and then find the" Location: LAC = 7101 CID = 1924c01 "in this column, the CELL ID is inside this CID.
    3.1.png
    Method 2: Use the LTE Discovery watch band states.
    NOTE: These two methods are there GCI (CID) guessing band, is only applicable to some of operators such as China Telecom, the absence of good planning China Unicom 4G CellID, and also China Mobile is not applicable for this .
    NOW@201504, we have LTE Discovery update to 3.19, support NEXUS6 display the real MODEM LTE Band!! thanks for Danial and his great team!!
    3.2.jpg Screenshot_2015-05-06-20-30-42.jpg Screenshot_2015-05-04-19-58-13.png Screenshot_2015-05-05-19-41-47.png
    While you want to Check real band PC tool QXDM may help if you have such tool, menu path is View-LTE- RRC layer-RRC/NAS Status Screen- Frequency band, wait for 10mintues for update or use airplane mode on/off to Tigger update.
    In case you are not in LTE covered area, but just want to check the qcn is applied or not, reset your phone in boot loader mode, select BP TOOLS again,them use QXDM-view-NV Browser-Item 06828- read to get the value, it should be 1099830466655 for add band1 while stock default is 1099830466654,
    Other qcn XT1103 add:
    B1/8 1099830466783
    B1/9/19 1099830729055
    B1/8/9/19 1099830729183
    XT1100 add:
    B2/4 1099646632415, @default 1099646632405

    Here we must thank:
    Q39705630 enthusiastic and efficient testing and Draft this tutorial V0.1 version;
    Q562552826 provide XT1103 of qcn file, doing preliminary analysis;
    Q386499038 provide XT1100 qcn file, do the final release qcn file parameter reference;​

    Other Reference Tutorial IN Chinese:


    1. CN version band1 enablement:
    http://bbs.gfan.com/android-7863761-1-1.html
    2.NEXUS6 RF parameters such as PC-side backup method qcn
    http://bbs.gfan.com/android-7741730-1-1.html
    3. Some tools on LTE band1 signal monitoring
    http://bbs.gfan.com/android-7684876-1-1.html
    10
    XT1100 to XT1103?
    Is it possible to convert an XT1100 to an XT1103? Is it a hardware thing?

    I would like to enable band 2 and 4 in the XT1100, is that at all possible?

    I have both an XT1103 (borrowed) and my own, an XT1100. Could I copy the NV values from the 1103 onto the 1100? Would it cause any damage to try?

    I dont mind formatting, but I also don't want a brick.

    Thanks,
    Sam.
    Sam, some is possible, but I do not have a due day for next qcn releasing.
    Hi sorry for muy english. I need to enable band 4 on nexus 6 xt 1100. Can you send NV values for do this.

    Thks.
    Marcelo

    Finally, I manage serveral my family hours to make some trial qcns for more bands, Including:
    Band 2 and band 4 for XT1100 View attachment XT1100_LTE_B2_B4_Patch.zip
    and Band 1 and band 8 or Band 1/9/19 or Band 1/8/9/19 for XT1103 View attachment XT1103_B1_B8_B9_B19_Patch.zip
    to trial.
    for new comers HOW TO questions, please read POST#1 first, just replace the qcn files attached named with the band you want.
    I have never test these qcn since no such band signal in my city, So YOUR feedback after 1 day test is preferred
    Your sucess will lead me to update the POST#1 1-stop with full info .

    AN important NOTE for XT1103 band 20, the fact is I have attached
    XT1103_B1_B8_B9_B19_Patch.zip\XT1100toXT1103_RF_LTE_B1_8_9_19_20_Merged.QCN here,
    but according my knowlege in NEXUS5, to enabled band 17 and band 20 at the same model will NEED addtional components in RF Front End hardware design, so mostly , XT1103 enabled Band17 will NOT support band20.
    so you are free to try XT1100toXT1103_RF_LTE_B1_8_9_19_20_Merged.QCN, but do not have too much hope to get band20 works.
    4

    Yes. I can not Choose where I was born, But I can choose whether I can contribute.
    While American Dream is on the Sky, Chinese Dream is running on the ground even we are weak, I am expecting to contribute for the global. haha
    3
    I just ran this process with QPST 2.7 Build 425. I am on an XT1103 in Switzerland for vacation and was not able to get Band 20 to work. The phone supports ALL the other bands that are used for LTE, but apparently the area that I am in on Swisscom is using 20. I flashed the file that says it has 20 in it, but I did see some notes from Azlan that he wasn't sure that 20 would work due to some kind of overlap with 17 that is already supported on the XT1103. Azlan, if you have anything you want me to try while i'm here, I'm in Switzerland/France for the next 7 days.

    Thanks for all your work on this, I'm sure most of the people that are successful don't ever come back and say thanks, just like everyone who posts ROMs, myself included. Thanks for what you do for the community.
    3
    Hi, I messed up my NV values and I can't get signal anymore. Can you please post original XT1103 QCN file so we can restore the backup? Thanks. :eek:
    Please note the normal QPST-Software Download backup qcn will not works for restoring,
    and older QPST-RF NV Item manager backuped Qcn can not cover all RF nv now, so it is also not good choice for you to restore Solutions for your issue,
    Soution1. In case you only lost your signal after you use 4636-Phone Info-Select UMTS band- US band, Try to set NV00441 to 0xFFFF with this qcn, by QPST-Software Download, an old post is here:
    http://xdaforums.com/nexus-6/help/help-locked-nexus-to-usa-band-t2975290/page2
    Solution2. for others failture reason, To NEXUS6 reflash the factory images will help to reset all your nv from backup eMMC partition,
    How to is here: http://xdaforums.com/nexus-6/general/guide-flash-factory-images-nexus-6shamu-t2954008