[G3 General] Hnk1:
USE AT YOUR OWN RISK

This guide is intended for those individuals who can not use 3g or LTE but 2g works perfectly for them or they have lost their network and flashing different radios does not help

To check if you have this problem,

go to settings>more>Mobile Network>Manual Search

You should have GSM / WDCMA/LTE or others depending on your network from all networks in your area.

What do you need :

*Drivers installed

*USB debugging (enable by going into settings>software information> tap on build number 10 times and developer options will appear in settings at the end. Enable USB debugging from there)

*ROOT

*QPST (QPST DOWNLOAD) LINK2

*EFS BACKUP TOOL (EFS BACKUP THREAD)

* Device specific backup of QCN (FIND IT YOURSELF AS IT WILL CHANGE YOUR IMEI TOO)

*DIAG MODE ENABLED

This is how to enable diag mode via platform tools using ADB on LG devices

adb shell
su
echo 1 > /sys/devices/platform/lg_diag_cmd/diag_enable
setprop sys.usb.config acm,diag,mtp,adb

It is preferred to clear these partitions by using these commands and restart your phone before flashing qcn files. I wiped wrong partitions (tz)using these commands and I got a HARD BRICK. YES A HARD BRICK so be very careful

dd if=/dev/zero of=/dev/block/mmcblk0p21
dd if=/dev/zero of=/dev/block/mmcblk0p22
dd if=/dev/zero of=/dev/block/mmcblk0p24

Restore by, where XX is the number and YY name of partition

dd if=/dev/block/[B]mmcblk0pXX/B] of=/sdcard/[B]YY[/B].epb

Example

dd if=/dev/block/mmcblk0p9 of=/sdcard/system.img

However, you can go ahead and clear these partitions only if you had a previous backup by blocks like EFS FILE EXPLORER. modemst1, modemst2, fsg, fsc,dbi, ddr, pad

Check which partition corresponds to which block by

ls -al /dev/block/platform/msm_sdcc.1/by-name

Once your device is connected, drivers and software installed,

You may need to first go to QPSTConfig which is located at QPST > Bin. There you will need to select port which will show your snapdragon model.

Go to QPST > Bin> QPSTServer.exe

1.A globe would appear in taskbar. Click on it and select software download.

2.Select port of your diagnostic mode in restore tab of software download

3. Once in software download, backup your current QCN (just as a backup to be safe)

4. Restore the QCN you found from google. Make sure it is device specific (use d850 QCN for d850 only)

5. Device would restart and automatically start to search 3g and LTE signals

Good luck

My original QCN was 31kb which clearly showed lost of data but the one that worked was about 500kb.

Lastly there are other methods to restore as well which I will look into so I can post in more details so your IMEI does not change.

Edit: You can do it by changing NV VALUE of 457 to your default value to keep your imei number as well

I will try to backup my radio partitions if someone needs help to fix their network issues or other possible solutions that could be found

HOW TO REVERT YOUR IMEI BACK TO ORIGINAL

1. Download EFS Professional. FROM HERE

2. Make sure you are rooted and busy box working.

3. Use commands as stated above to boot your phone in DIAG mode. This can be done anytime after connecting your phone to the PC.

4. Go to Qualcomm NV tools

5. Choose right port and connect.

6 Go to Secure Ops. tab and change imei from there. Make sure you have a full backup.

If this fails, you can use QXDM and go to NV tools and manually change your IMEI back to its real value. You will need to go to NV Values tab and then on side tab choose Security from All, and then change IMEI number to your real one. You can check details how to change values in QXDM in futher reading below. Samsung S5 thread explains it really well.

If you still are not sure, you can use QPST software. Go to NV manager and find your IMEI number after connecting the phone in diag mode. Usually it is 550 or 457 value.

Use Imei converter from attached files below and insert the converted values.

Good Luck

THREADS TO LOOK FOR FURTHER READ

Unlock Bands and how to boot into Diag mode All credits to [MENTION=4300205]olokos[/MENTION] for his guide

Unlock LTE bands and go into diag mode

All credits to [MENTION=5353566]fffft[/MENTION] for his guide

FOR BEST RESULTS WHICH I FOUND HAD MORE SUCCESS WITH

1. First understand the problem fully here

2. Flash a working qcn to your device

3. Wipe partitions as commands given above

4. restart

5. Flash a working qcn on it again. Preferably the same one

6. Check if you get signals now, if not then do a factory reset and see

Profit ? No

7. Install TOT stock 4.4.2 or Lollipop (I had more success with Lollipop)

8. Install a qcn from another device. Just to break all your signals (do at your own risk) I flashed a D855 qcn to my d850

9. Restart and wipe partitions

10. Reflashed working Qcn again

Profit ? No

It did not work till here so I moved to stock lollipop by flashing zip in TWRP. If you have TOT method, that is better.

So I went to flash Lollipop stock with modem of D850. (because it was zip and did not include modem. In TOT/ KDZ all partitions are flashed so you do not need to flash modem separately) So i wiped partitions again and then I flashed QCN using cracked version of Z3x Lg Tools twice. (same qcn but two times) and then restarted.

It restored everything back. Everything came to work fine

Z3X Cracked Download here

WHAT YOU CAN DO TO HELP OTHERS (needs root and busybox installed)

I suggest you make a backup of your EFS via TWRP & EFS TOOL before tinkering with hidden menu or anything at all. If you do these steps correctly, you do not risk of any damage to your device.

Download EFS Tool from here

http://xdaforums.com/atta...6&d=1419867628

Main thread of it

http://xdaforums.com/gala...546?styleid=18

1. go in backup tab

2. select all partitions

3. Select 3 partitions

backup modem, modemst1 and modemst2 and upload it for me so I can try to restore the settings to see if that works.

MAKE SURE YOU WRITE YOUR DEVICE MODEL when attaching those mentioned partitions AND DOUBLE CHECK IT AS FLASHING WRONG radios can permanently damage your device.

DEVICE I FIXED WAS D850 ATT Variant and had success with other variants as well

UPDATE

I have attached a D855 qcn with null imei. You will need to change your imei yourself which you can find by removing your battery. Make sure to make a backup before trying anything and I WILL BE NOT RESPONSIBLE

HISTORY --- JUST TO COMPARE IF YOU HAVE SIMILAR PROBLEM

hi there,

I am working to fix the problem many users have faced and therefore trying to find possible solutions. I need some partition images from you guys if you can provide me so I can try to fix the issues.

THE PROBLEM AND HOW IT STARTED :

I have got a D850 which I am using in Europe. The problem started when I inserted an LTE enabled sim and went to hidden menu to change my mode to LTE only, I was on Fulmics Rom 2.7 Lollipop at that time. Before that, ii network search, I could see all WCDMA, GSM and LTE bands used by different providers by manual search.

After changing it to LTE only, I could not see any signal bars and it started searching. As I was in an area where LTE signals were weak, so I thought maybe I need to change back to GSM/WCDMA/LTE from settings. Signals returned to normal but only to gsm. LTE and 3G were lost as searching for networks did not help at all.

I tinkered with hidden menu and selected GSM/WCDMA/LTE ( 3845#*850# ) from hidden menu

and

used this ( *#*#4636#*#* ) to change back to GSM/WCDMA/LTE from another hidden menu.

It didnot help.

I flashed different modems (one from kitkat and two versions from Lollipop) but that didnot help either.

I reverted back to KITKAT using TOT method and the WCDMA and LTE were lost forever when i tried to search manually. So I made an EFS backup and started tinkering with hidden method.

Actually I was not expecting that the values would be affected by using the hidden menu to fix my network to LTE only.

I then backup my EFS and tinkered with hidden menu and i was successful in bringing back LTE, however, I was stuck with no 3g.

Using build prop editor, I changed my operator from ATT to OPEN (as ATT does not show default selection menu for GSM/WCDMA/LTE in settings/ both hidden menus) which enabled the option by which I could changed my preferred network type.

In hidden menu, I just enabled VoLTE in LTE > Modem Settings > VoLTE On which brought back LTE.

Next I installed QPST & QXDM to check my NV values and IMEI.

All of those were perfectly fine. No problem at all.

Strangely all the NV values are right. I restored my EFS to old state where I didnot have LTE or 3g. The LTE was gone again.

I again enabled VoLTE from hidden menu and LTE came back.

See attached image for reference.

POSSIBLE SOLUTION :

I think the problem lies in ATT settings as it has preset operator settings which changes from GSM to WCDMA to LTE depending on its values.

Once I selected LTE only, I disabled the WCDMA and somehow broke the AT&T preset settings as you can not change preferred network from settings like D855 or other models. Somehow we need to re-enable these and one possible way would be to flash modemst 1 and modemst 2 from backup.

Please help me find the possible solution

PS : For all those who are wondering if i tried other sims and tried to use 4g/3g on another device. Yes i did and the problem is only in D850

I also made a proper working APN. Plus I check which network I am on by using *#*#4636#*#*

ANY SUGGESTIONS ?[/U][/COLOR][/B] [MENTION=2607037]hyelton[/MENTION]

People who can not flash QCN need to break their Lg lock which is done by flashing someone else Twrp backup of same device on your phone. After this, you will be able to flash QCN without issues