[Tutorial] Crossflash, Bypass OPID Mismatched Error

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Chris3445

Member
Jan 22, 2023
32
1
Hello all I did the above steps to get my phone crossed flashed to can version but the problem im having now is this the phone I have is a LG g8x att model lmg850um20o was the firmware I was on be for I crossed flashed it any help would be appreciated thanks
 

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Mister Follbe

New member
Jul 19, 2022
4
1
After crossflash on LG G8X everything works fine, but device is not certified in Google Play Protect (Google Pay does not work). No one knows how to solve the problem without Root?
 

amerkhan139

New member
Feb 12, 2023
2
0
Thanks, netmsm and kt-froggy for the guides.
I figured out how to remove the NT code error without root.
You will first need a file manager that can access the root directory.
I personally used "Solid Explorer File Manager" to access the cust_path_mapping.cfg file to read the NT-Code that came with the firmware.
You can use the Solid Explorer File Manager to access the root directory by going to settings then scrolling down and checking the box "show root storage". You will now be able to access the root storage.
You can access the cust_path_mapping.cfg by going to root/system/product/OP. Then open the file and note the code. Mine was FFFFFF,82=/product/OP.
Create a backup of the FTM partition the open the FTM file with HxD app. (Make sure you have a copy of the FTM file in case something goes wrong)
Go to line 00014000 and edit the line. depending on the phone, edit the first 2 sets of numbers/letters with 3 characters separated by a comma. ("FFF,FFF), then the last set of numbers/letters with 2 characters to match the code in the cust_path_mapping.cfg file.
(Mine was
"2","310,120,FFFFFFFF,FFFFFFFF,FF","312,530,FFFFFFFF,FFFFFFFF,FF" and I changed to
"2","FFF,FFF,FFFFFFFF,FFFFFFFF,82","FFF,FFF,FFFFFFFF,FFFFFFFF,82") because I was getting NT code error
310120, 312530 ; FF, FF

Note:
1. The line could span from 00014000 to 00014040 like mine. Each line is separated with "". I had 2 lines and had to change both lines. You can have only 1 line
2. Make sure you don't delete the line but just select the content and overwrite it with new text. deleting might affect other lines below with content. ( I deleted some lines and my phone factory reset)


After that just save the FTM and load it to your phone using QFIL and the error will be gone.

I've only tested it on my LG G8, OPEN CA firmware so I'm not sure if it will work on others.
Sir please send lg V500N Original Stock ftm.bin Backup
 

Mister Follbe

New member
Jul 19, 2022
4
1
After crossflash (Sprint -> DEU) LG G8X lost Play Protect certification (Google Pay does not work). Does anyone know how to solve the problem without root?

For information: after the first crossflash the certification was, after subsequent ones no longer... I tried to unlock and then relock bootloader (it was mentioned on one forum that after this the certification will return), but it did not work for me.
 
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Bons007

Member
Jan 28, 2022
20
1
Xperia XZ2
can i
Hi there ;)
Thanks to all other guys here who have made helpful development to tame this beautiful =)

To crossflash models other than LG G8 please read post 3.
Before asking any question please read the troubleshooting section at the bottom of the page.
If you still need some specific help I would appreciate if you bring it up just in the thread instead of sending direct messages.


LG has made things difficult in flashing custom and even stock roms by this new OPID thing! It prevents us from crossflashing but we have been able to use TWRP and change the system and some other partitions to have a different rom. We had to make some changes into OP partition using HxD editor.
But now, through this tutorial, we're able to flash any rom without the need to change OPID in OP partition. Also, there is no need to root or unlock boot-loader.
I was successful to do this on some G8 (LMG820UM) but I AM NOT RESPONSIBLE FOR ANY HARM TO YOUR PHONE!

By continuing to read the following instructions you are actually accepting the risk.


IMPORTANT!
first, MAKE A FULL BACKUP OF ALL PARTITIONS; and I mean it!!!
at least, for your sake, make a backup of "modemst1, modemst2, fsg, fsc, ftm" partitions, for emergency.


Requirements
QPST and Qualcomm USB Driver (get)
LGE SM8150 Firehose (get)
LGUP 1.16.0.3 (get)
LGUP_Common.dll (get)
UI_Config.lgl (get)
LG Mobile Driver 4.4.2 (get)


Preparation
1. Install QPST and Qualcomm USB Driver.
2. Install LGUP.
3. Find the folder named "model" in the installation directory of LGUP, then Create a folder named "common" in the "model" folder.
4. Move "LGUP_Common.dll" and "UI_Config.lgl" into "common" folder. Change the attribute of "UI_Config.lgl" to read only.
5. Install LG Mobile Driver 4.4.2.


Steps
A)
1. Open QFIL.
2. Change "Storage Type" to UFS.
3. Select "Flat Build".
4. Browse for "LGE SM8150 Firehose" and pick it.
5. Now, connect the phone to PC and boot into EDL mode.
6. Open "Select Port" and select the phone, press OK.
7. In "Tools" open the "Partition Manager".

B)
!!!BE CAREFUL TO DO EXACTLY AS THE INSTRUCTIONS SAY OR YOU WILL BRICK THE PHONE!!!
1. Make a backup of and erase these 7 partitions: FTM, Modem_A, Modem_B, SID_A, SID_B, OP_A, OP_B.
1.1. You have to left-click on a partition then right-click on it and select "Manage Partition Data".
1.2. In the pop-up window, you have 4 choices: I. Erase (to erase data on the partition), II. Read Data (to dump or back up the partition), III. Load Image (to restore the partition), IV. Close (to close the window).
1.3. First dump/back up the partition by choosing "Read Data" then Erase it.
2. Close the "Partition Manager" window.
3. Wait for 5 seconds then press Vol- and Power until it restarts.
3.1. Immediately after rebooting, Release the Vol- and Power buttons and press Vol+ to get into Download Mode.
Note: Do not let the phone to begin to boot! If it begins to boot, it may regenerate the SID and FTM partitions data and so you need to redo the whole step B.

C)
1. Open LGUP.
2. Pick your favorite KDZ.
3. Select "PARTITION DL".
4. Press Start. And a pop-up window will appear. In this window you can select which partitions to be flashed.
5. Here, uncheck these partitions: SID_A and SID_B. It will make it able to bypass the OPID Mismatched Error.
6. If you are in Sprint or other platforms you will get the message whether to change the model or not. Of course you know what to do =)

after completing the process it will boot up in some minutes and before starting the customization it will do one restart. just be patient.


ERRORS, QUESTIONS, TROUBLESHOOTING
1. Can I crossflash V50, V60, G8X or other LG devices using this method?
I did it on V50. Maybe it'll work on your devices maybe won't. There's one way to find out; make backup and give it a try.
2. SN is gone, zero, etc.
Restore your original FTM.
3. I can't get into recovery.
Restore the original FTM.
4. I got NT-Code error.
It's been discussed many times in the thread and some solutions have been presented (such as this one, thanks to @animo214 and this, thanks to @kt-Froggy as well as this one, thanks to @StvOchi ). However, you can ignore it if the phone got network.
Note: You need to disable verity on the phone in advance otherwise changes in cust_path_mapping.cfg won't be saved.
5. IMEI is lost, zero, null etc.
Restore LUN5 partitions. If you have no backup it should be repaired using Octopus box. Go to 16.
6. I got "permanently locked" error.
This is because of IMPL lock and you have to restore LUN5 partitions. In case of having no backup you should use Octopus box.
7. All partitions are deleted accidentally.
Follow this instructions.
8. I need to get into PDM mode.
Unzip and restore the attached PDM to FTM partition. Remember, you need to restore your FTM to get into OS.
9. Can I use another phone's LUN5 backup?
NO.
10. Can I use another phone's FTM backup?
Yes. All partitions can be restored from another phone's backup except LUN5 partitions.
11. My phone is stuck in boot-loop.
Restore the original FTM and if it doesn't help redo the whole crossflash process and use a different KDZ this time.
12. Which KDZ is the best (for any matter of use)?
I do not know.
13. Can I crossflash from any source variant to Korean variant or vice versa?
Yes it is possible but you may get error on opening stock camera application because of hardware differences. There are some methods to solve the issue which you can search and find them.
14. Can I downgrade using this method?
Yes.
15. I erased partitions (ftm, op_a, op_b, modem_a, modem_b, sid_a, sid_b) but it still does not let me to crossflash.
Redo the whole process and this time make backup of and erase these partitions too, on both sides A and B: vendor, product, system, boot and userdata. Do not make backup of userdata partition.
16. How can I write IMEI?
A) Dump modem_a and create a copy of it. Then open it in UltraISO and remove IMEIPROT files from image folder. Save and restore it in place of modem_a and modem_b partitions.
B) Make backup of FTM and then flash or restore the PDM file (attached) into your ftm partition. Restart the phone; you'll get into PDM mode.
C) Open Tutty (attached). Select "Serial" in protocol and the proper port of your phone's modem driver. Click open. To test if you have selected the proper port number type "at" and hit enter it should respond"ok". Type the code at%imei=# (replace # with your IMEI) and hit enter. It doesn't matter you get "error" or "ok" after that, just check if IMEI is written via this code at%imei=?. If IMEI is written so you'll have the right MEID and ESN too.
D) Restore the original ftm and modem_a in place of modem_a and modem_b. Restart the phone.
I've already tested this method on V30, V50 and G8. Remember, if the phone has IMPL lock it'll throw "perm. locked" error even if you have written the IMEI.
17. I have lost GPT files of my LG G8, G8X, G8S, V50, etc. and Qfil partition manager does not show anything in the list.
You need to flash GPT files to your device with fh_loader (see this, part C). For that matter use KDZ_Tools to Extract DZ from a KDZ of your device. Then extract the DZ using -c at the end of extracting command. For example: unkdz -f FILE_NAME.kdz -c. It will extract all files besides all GPTs.
18. Which are the LUN5 partitions?
SM8150 has 7 physical partitions known as LUNs which are numbered from 0 to 6. Each LUN is split into several partitions. In Qfil Partition Manager you can see all partitions except those of LUN3 and LUN6 which are hidden. The number of LUNs are shown under the first column named LUN. Therefore, all partitions in front of number 5 are LUN5 partitions.
can we use article 16 to change imei i know its illegal but its also a question can be answered in yes or no
 

sasindu

Member
Oct 10, 2012
37
9
Hi there ;)
Thanks to all other guys here who have made helpful development to tame this beautiful =)

To crossflash models other than LG G8 please read post 3.
Before asking any question please read the troubleshooting section at the bottom of the page.
If you still need some specific help I would appreciate if you bring it up just in the thread instead of sending direct messages.


LG has made things difficult in flashing custom and even stock roms by this new OPID thing! It prevents us from crossflashing but we have been able to use TWRP and change the system and some other partitions to have a different rom. We had to make some changes into OP partition using HxD editor.
But now, through this tutorial, we're able to flash any rom without the need to change OPID in OP partition. Also, there is no need to root or unlock boot-loader.
I was successful to do this on some G8 (LMG820UM) but I AM NOT RESPONSIBLE FOR ANY HARM TO YOUR PHONE!

By continuing to read the following instructions you are actually accepting the risk.


IMPORTANT!
first, MAKE A FULL BACKUP OF ALL PARTITIONS; and I mean it!!!
at least, for your sake, make a backup of "modemst1, modemst2, fsg, fsc, ftm" partitions, for emergency.


Requirements
QPST and Qualcomm USB Driver (get)
LGE SM8150 Firehose (get)
LGUP 1.16.0.3 (get)
LGUP_Common.dll (get)
UI_Config.lgl (get)
LG Mobile Driver 4.4.2 (get)


Preparation
1. Install QPST and Qualcomm USB Driver.
2. Install LGUP.
3. Find the folder named "model" in the installation directory of LGUP, then Create a folder named "common" in the "model" folder.
4. Move "LGUP_Common.dll" and "UI_Config.lgl" into "common" folder. Change the attribute of "UI_Config.lgl" to read only.
5. Install LG Mobile Driver 4.4.2.


Steps
A)
1. Open QFIL.
2. Change "Storage Type" to UFS.
3. Select "Flat Build".
4. Browse for "LGE SM8150 Firehose" and pick it.
5. Now, connect the phone to PC and boot into EDL mode.
6. Open "Select Port" and select the phone, press OK.
7. In "Tools" open the "Partition Manager".

B)
!!!BE CAREFUL TO DO EXACTLY AS THE INSTRUCTIONS SAY OR YOU WILL BRICK THE PHONE!!!
1. Make a backup of and erase these 7 partitions: FTM, Modem_A, Modem_B, SID_A, SID_B, OP_A, OP_B.
1.1. You have to left-click on a partition then right-click on it and select "Manage Partition Data".
1.2. In the pop-up window, you have 4 choices: I. Erase (to erase data on the partition), II. Read Data (to dump or back up the partition), III. Load Image (to restore the partition), IV. Close (to close the window).
1.3. First dump/back up the partition by choosing "Read Data" then Erase it.
2. Close the "Partition Manager" window.
3. Wait for 5 seconds then press Vol- and Power until it restarts.
3.1. Immediately after rebooting, Release the Vol- and Power buttons and press Vol+ to get into Download Mode.
Note: Do not let the phone to begin to boot! If it begins to boot, it may regenerate the SID and FTM partitions data and so you need to redo the whole step B.

C)
1. Open LGUP.
2. Pick your favorite KDZ.
3. Select "PARTITION DL".
4. Press Start. And a pop-up window will appear. In this window you can select which partitions to be flashed.
5. Here, uncheck these partitions: SID_A and SID_B. It will make it able to bypass the OPID Mismatched Error.
6. If you are in Sprint or other platforms you will get the message whether to change the model or not. Of course you know what to do =)

after completing the process it will boot up in some minutes and before starting the customization it will do one restart. just be patient.


ERRORS, QUESTIONS, TROUBLESHOOTING
1. Can I crossflash V50, V60, G8X or other LG devices using this method?
I did it on V50. Maybe it'll work on your devices maybe won't. There's one way to find out; make backup and give it a try.
2. SN is gone, zero, etc.
Restore your original FTM.
3. I can't get into recovery.
Restore the original FTM.
4. I got NT-Code error.
It's been discussed many times in the thread and some solutions have been presented (such as this one, thanks to @animo214 and this, thanks to @kt-Froggy as well as this one, thanks to @StvOchi ). However, you can ignore it if the phone got network.
Note: You need to disable verity on the phone in advance otherwise changes in cust_path_mapping.cfg won't be saved.
5. IMEI is lost, zero, null etc.
Restore LUN5 partitions. If you have no backup it should be repaired using Octopus box. Go to 16.
6. I got "permanently locked" error.
This is because of IMPL lock and you have to restore LUN5 partitions. In case of having no backup you should use Octopus box.
7. All partitions are deleted accidentally.
Follow this instructions.
8. I need to get into PDM mode.
Unzip and restore the attached PDM to FTM partition. Remember, you need to restore your FTM to get into OS.
9. Can I use another phone's LUN5 backup?
NO.
10. Can I use another phone's FTM backup?
Yes. All partitions can be restored from another phone's backup except LUN5 partitions.
11. My phone is stuck in boot-loop.
Restore the original FTM and if it doesn't help redo the whole crossflash process and use a different KDZ this time.
12. Which KDZ is the best (for any matter of use)?
I do not know.
13. Can I crossflash from any source variant to Korean variant or vice versa?
Yes it is possible but you may get error on opening stock camera application because of hardware differences. There are some methods to solve the issue which you can search and find them.
14. Can I downgrade using this method?
Yes.
15. I erased partitions (ftm, op_a, op_b, modem_a, modem_b, sid_a, sid_b) but it still does not let me to crossflash.
Redo the whole process and this time make backup of and erase these partitions too, on both sides A and B: vendor, product, system, boot and userdata. Do not make backup of userdata partition.
16. How can I write IMEI?
A) Dump modem_a and create a copy of it. Then open it in UltraISO and remove IMEIPROT files from image folder. Save and restore it in place of modem_a and modem_b partitions.
B) Make backup of FTM and then flash or restore the PDM file (attached) into your ftm partition. Restart the phone; you'll get into PDM mode.
C) Open Tutty (attached). Select "Serial" in protocol and the proper port of your phone's modem driver. Click open. To test if you have selected the proper port number type "at" and hit enter it should respond"ok". Type the code at%imei=# (replace # with your IMEI) and hit enter. It doesn't matter you get "error" or "ok" after that, just check if IMEI is written via this code at%imei=?. If IMEI is written so you'll have the right MEID and ESN too.
D) Restore the original ftm and modem_a in place of modem_a and modem_b. Restart the phone.
I've already tested this method on V30, V50 and G8. Remember, if the phone has IMPL lock it'll throw "perm. locked" error even if you have written the IMEI.
17. I have lost GPT files of my LG G8, G8X, G8S, V50, etc. and Qfil partition manager does not show anything in the list.
You need to flash GPT files to your device with fh_loader (see this, part C). For that matter use KDZ_Tools to Extract DZ from a KDZ of your device. Then extract the DZ using -c at the end of extracting command. For example: unkdz -f FILE_NAME.kdz -c. It will extract all files besides all GPTs.
18. Which are the LUN5 partitions?
SM8150 has 7 physical partitions known as LUNs which are numbered from 0 to 6. Each LUN is split into several partitions. In Qfil Partition Manager you can see all partitions except those of LUN3 and LUN6 which are hidden. The number of LUNs are shown under the first column named LUN. Therefore, all partitions in front of number 5 are LUN5 partitions.
Hi netmsm.
Iam currently using open kor android 10 firmware on my lm g820n, which was on skt firmware earlier, thanks to ur guide. Now that the lg g8 has received android 12 i tried to update it through check for updates on my phone and it shows that it's on the latest update, weird.
I just want to know which is the easiest way to get open kor android 12 on my device.
Is it possible to directly flash open kor android 12 according to the guide? OR should i flash skt android 10, then update to android 12 and then crossflash to open kor android 12?


Thanks in advance.
 

netmsm

Senior Member
Oct 3, 2010
559
276
Esfahan
LG V30
Hi netmsm.
Iam currently using open kor android 10 firmware on my lm g820n, which was on skt firmware earlier, thanks to ur guide. Now that the lg g8 has received android 12 i tried to update it through check for updates on my phone and it shows that it's on the latest update, weird.
I just want to know which is the easiest way to get open kor android 12 on my device.
Is it possible to directly flash open kor android 12 according to the guide? OR should i flash skt android 10, then update to android 12 and then crossflash to open kor android 12?


Thanks in advance.
Hi sasindu =)
The message saying you're on the latest update also happens for me. It's common I guess.
Yes it is possible to flash Open KOR A12 following the guide and you do not have to go the second way to return to SKT and...
 

sasindu

Member
Oct 10, 2012
37
9
Hi sasindu =)
The message saying you're on the latest update also happens for me. It's common I guess.
Yes it is possible to flash Open KOR A12 following the guide and you do not have to go the second way to return to SKT and...
Thanks for the reply. Ill try with open kor android 12 then.
One more question netmsm,
Are these partitions automatically generated by the OS? And what does they do?

Thank you.
 

ddeslandes1

Member
Feb 22, 2023
9
3
LG G8X ThinQ
I have succesfully crossflash the canadian android 12 (40c) rom to my USA AT&T G8X but I keep getting the NT error with a bunch of numeric values when booting. I know it does not alter the functionalities but I would like to get rid of it.

How can I do that ? I am getting last in all these readings

phone is not rooted nor bootloader unlocked

thanks for your help!
 
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nortnil

Senior Member
Jul 8, 2010
50
10
I have the LM-G820QM version, and I have previously cross flashed to the official Verizon ROM. This got wifi calling on this phone to work for me, but the Verizon ROM is hot garbage so I flashed back to the OEM ROM which of course broke wifi calling.

Is there anyway to Frankenstein together whatever modem/carrier stuff enables wifi calling on the Verizon ROM with the OEM ROM so I can get wifi calling without the trash Verizon ROM?
 

Surgemanxx

Senior Member
Jun 21, 2022
426
184
LG V30
LG G7 ThinQ
I have succesfully crossflash the canadian android 12 (40c) rom to my USA AT&T G8X but I keep getting the NT error with a bunch of numeric values when booting. I know it does not alter the functionalities but I would like to get rid of it.

How can I do that ? I am getting last in all these readings

phone is not rooted nor bootloader unlocked

thanks for your help!
It's all under questions,answer,and troubleshooting in the main post.Read this section here to fix the NT Code issues.

ERRORS, QUESTIONS, TROUBLESHOOTING
1
. Can I crossflash V50, V60, G8X or other LG devices using this method?
I did it on V50. Maybe it'll work on your devices maybe won't. There's one way to find out; make backup and give it a try.
2. SN is gone, zero, etc.
Restore your original FTM.
3. I can't get into recovery.
Restore the original FTM.
4. I got NT-Code error.
It's been discussed many times in the thread and some solutions have been presented (such as this one, thanks to @animo214 and this, thanks to @kt-Froggy as well as this one, thanks to @StvOchi ). However, you can ignore it if the phone got network.

For open Canada,you'll need to add this NT Code to your FTM partition for the NT Code.If you can pull your FTM with Qfil,send it to me and I'll fix it for you.

"1","FFF,FFF,FFFFFFFF,FFFFFFFF,82"
 
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Surgemanxx

Senior Member
Jun 21, 2022
426
184
LG V30
LG G7 ThinQ
I have the LM-G820QM version, and I have previously cross flashed to the official Verizon ROM. This got wifi calling on this phone to work for me, but the Verizon ROM is hot garbage so I flashed back to the OEM ROM which of course broke wifi calling.

Is there anyway to Frankenstein together whatever modem/carrier stuff enables wifi calling on the Verizon ROM with the OEM ROM so I can get wifi calling without the trash Verizon ROM?
From what I have read and tried it's not possible!When the device boots and connects to the network,it sends data back to see what the actual firmware is running on the device and it enables features from there.I'm not saying there isn't a way,but from my experience it's almost impossible!
 

nortnil

Senior Member
Jul 8, 2010
50
10
From what I have read and tried it's not possible!When the device boots and connects to the network,it sends data back to see what the actual firmware is running on the device and it enables features from there.I'm not saying there isn't a way,but from my experience it's almost impossible!
That's unfortunate, but thanks for saving me the grief of trying to find creative solutions that don't exist. Verizon has the best coverage in the mountains, but sucks in every other way. It's an obnoxious catch 22.
 

Surgemanxx

Senior Member
Jun 21, 2022
426
184
LG V30
LG G7 ThinQ
That's unfortunate, but thanks for saving me the grief of trying to find creative solutions that don't exist. Verizon has the best coverage in the mountains, but sucks in every other way. It's an obnoxious catch 22.
I'm in Nashville,TN. and Verizon is the best service we have period at the moment!I currently have a Verizon LG G7 I had to do the same similar way with crossflashing it to get the IMS working on AT&T.No WiFi calling,but VoLTE works 100%.
 
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  • 55
    Hi there ;)
    Thanks to all other guys here who have made helpful development to tame this beautiful =)

    To crossflash models other than LG G8 please read post 3.
    Before asking any question please read the troubleshooting section at the bottom of the page.
    If you still need some specific help I would appreciate if you bring it up just in the thread instead of sending direct messages.


    LG has made things difficult in flashing custom and even stock roms by this new OPID thing! It prevents us from crossflashing but we have been able to use TWRP and change the system and some other partitions to have a different rom. We had to make some changes into OP partition using HxD editor.
    But now, through this tutorial, we're able to flash any rom without the need to change OPID in OP partition. Also, there is no need to root or unlock boot-loader.
    I was successful to do this on some G8 (LMG820UM) but I AM NOT RESPONSIBLE FOR ANY HARM TO YOUR PHONE!

    By continuing to read the following instructions you are actually accepting the risk.


    IMPORTANT!
    first, MAKE A FULL BACKUP OF ALL PARTITIONS; and I mean it!!!
    at least, for your sake, make a backup of "modemst1, modemst2, fsg, fsc, ftm" partitions, for emergency.


    Requirements
    QPST and Qualcomm USB Driver (get)
    LGE SM8150 Firehose (get)
    LGUP 1.16.0.3 (get)
    LGUP_Common.dll (get)
    UI_Config.lgl (get)
    LG Mobile Driver 4.4.2 (get)


    Preparation
    1. Install QPST and Qualcomm USB Driver.
    2. Install LGUP.
    3. Find the folder named "model" in the installation directory of LGUP, then Create a folder named "common" in the "model" folder.
    4. Move "LGUP_Common.dll" and "UI_Config.lgl" into "common" folder. Change the attribute of "UI_Config.lgl" to read only.
    5. Install LG Mobile Driver 4.4.2.


    Steps
    A)
    1. Open QFIL.
    2. Change "Storage Type" to UFS.
    3. Select "Flat Build".
    4. Browse for "LGE SM8150 Firehose" and pick it.
    5. Now, connect the phone to PC and boot into EDL mode.
    6. Open "Select Port" and select the phone, press OK.
    7. In "Tools" open the "Partition Manager".

    B)
    !!!BE CAREFUL TO DO EXACTLY AS THE INSTRUCTIONS SAY OR YOU WILL BRICK THE PHONE!!!
    1. Make a backup of and erase these 7 partitions: FTM, Modem_A, Modem_B, SID_A, SID_B, OP_A, OP_B.
    1.1. You have to left-click on a partition then right-click on it and select "Manage Partition Data".
    1.2. In the pop-up window, you have 4 choices: I. Erase (to erase data on the partition), II. Read Data (to dump or back up the partition), III. Load Image (to restore the partition), IV. Close (to close the window).
    1.3. First dump/back up the partition by choosing "Read Data" then Erase it.
    2. Close the "Partition Manager" window.
    3. Wait for 5 seconds then press Vol- and Power until it restarts.
    3.1. Immediately after rebooting, Release the Vol- and Power buttons and press Vol+ to get into Download Mode.
    Note: Do not let the phone to begin to boot! If it begins to boot, it may regenerate the SID and FTM partitions data and so you need to redo the whole step B.

    C)
    1. Open LGUP.
    2. Pick your favorite KDZ.
    3. Select "PARTITION DL".
    4. Press Start. And a pop-up window will appear. In this window you can select which partitions to be flashed.
    5. Here, uncheck these partitions: SID_A and SID_B. It will make it able to bypass the OPID Mismatched Error.
    6. If you are in Sprint or other platforms you will get the message whether to change the model or not. Of course you know what to do =)

    after completing the process it will boot up in some minutes and before starting the customization it will do one restart. just be patient.


    ERRORS, QUESTIONS, TROUBLESHOOTING
    1. Can I crossflash V50, V60, G8X or other LG devices using this method?
    I did it on V50. Maybe it'll work on your devices maybe won't. There's one way to find out; make backup and give it a try.
    2. SN is gone, zero, etc.
    Restore your original FTM.
    3. I can't get into recovery.
    Restore the original FTM.
    4. I got NT-Code error.
    It's been discussed many times in the thread and some solutions have been presented (such as this one, thanks to @animo214 and this, thanks to @kt-Froggy as well as this one, thanks to @StvOchi ). However, you can ignore it if the phone got network.
    Note: You need to disable verity on the phone in advance otherwise changes in cust_path_mapping.cfg won't be saved.
    5. IMEI is lost, zero, null etc.
    Restore LUN5 partitions. If you have no backup it should be repaired using Octopus box. Go to 16.
    6. I got "permanently locked" error.
    This is because of IMPL lock and you have to restore LUN5 partitions. In case of having no backup you should use Octopus box.
    7. All partitions are deleted accidentally.
    Follow this instructions.
    8. I need to get into PDM mode.
    Unzip and restore the attached PDM to FTM partition. Remember, you need to restore your FTM to get into OS.
    9. Can I use another phone's LUN5 backup?
    NO.
    10. Can I use another phone's FTM backup?
    Yes. All partitions can be restored from another phone's backup except LUN5 partitions.
    11. My phone is stuck in boot-loop.
    Restore the original FTM and if it doesn't help redo the whole crossflash process and use a different KDZ this time.
    12. Which KDZ is the best (for any matter of use)?
    I do not know.
    13. Can I crossflash from any source variant to Korean variant or vice versa?
    Yes it is possible but you may get error on opening stock camera application because of hardware differences. There are some methods to solve the issue which you can search and find them.
    14. Can I downgrade using this method?
    Yes.
    15. I erased partitions (ftm, op_a, op_b, modem_a, modem_b, sid_a, sid_b) but it still does not let me to crossflash.
    Redo the whole process and this time make backup of and erase these partitions too, on both sides A and B: vendor, product, system, boot and userdata. Do not make backup of userdata partition.
    16. How can I write IMEI?
    A) Dump modem_a and create a copy of it. Then open it in UltraISO and remove IMEIPROT files from image folder. Save and restore it in place of modem_a and modem_b partitions.
    B) Make backup of FTM and then flash or restore the PDM file (attached) into your ftm partition. Restart the phone; you'll get into PDM mode.
    C) Open Tutty (attached). Select "Serial" in protocol and the proper port of your phone's modem driver. Click open. To test if you have selected the proper port number type "at" and hit enter it should respond"ok". Type the code at%imei=# (replace # with your IMEI) and hit enter. It doesn't matter you get "error" or "ok" after that, just check if IMEI is written via this code at%imei=?. If IMEI is written so you'll have the right MEID and ESN too.
    D) Restore the original ftm and modem_a in place of modem_a and modem_b. Restart the phone.
    I've already tested this method on V30, V50 and G8. Remember, if the phone has IMPL lock it'll throw "perm. locked" error even if you have written the IMEI.
    17. I have lost GPT files of my LG G8, G8X, G8S, V50, etc. and Qfil partition manager does not show anything in the list.
    You need to flash GPT files to your device with fh_loader (see this, part C). For that matter use KDZ_Tools to Extract DZ from a KDZ of your device. Then extract the DZ using -c at the end of extracting command. For example: unkdz -f FILE_NAME.kdz -c. It will extract all files besides all GPTs.
    18. Which are the LUN5 partitions?
    SM8150 has 7 physical partitions known as LUNs which are numbered from 0 to 6. Each LUN is split into several partitions. In Qfil Partition Manager you can see all partitions except those of LUN3 and LUN6 which are hidden. The number of LUNs are shown under the first column named LUN. Therefore, all partitions in front of number 5 are LUN5 partitions.
    7
    First off, big THANKS to the OP (netmsm) and other people who contributed to this thread and made this guide very clear and useful!

    So, after perusing this thread for a long time, trying to understand the ins and outs of the process and any possible snafus, I decided to take the plunge after the Open_CA A12 (40a) got released recently, and to flash it onto my G8 originally from US Cellular. The crossflash went smoothly with no issues at all. A nice surprise was that the BL remained unlocked - I was prepared to go through the whole unlocking process again before rooting, but didn't have to. I got the empty S/N (easy fix), and the infamous NT-Code error. This is where I got stuck for a while. I tried fixing it by editing the cust_path_mapping.cfg file as suggested in the thread. The problem is that I couldn't save the changes in that stupid file by using ANY root explorer/editor! :mad: Tried half a dozen different apps with no luck at all. BTW, anyone has any ideas what I may have been doing wrong?? Yes, I am properly rooted with Magisk.

    Anyway... Everything worked fine on the phone, but that lame error was really getting under my skin - I could have ignored it, but I hated not being able to get rid of it. So... After more reading, I came across some info on hex-editing the FTM partition (in a totally unrelated topic). The NT-Code in FTM binary is stored at the offset 00014000. My error message was referring to the code "FFFFFF,85". The original cust_path_mapping.cfg file (which I couldn't edit) had a line referring to "FFFFFF,82". So, having all backups available, I decided, just for the heck of it, to change the last digits of the NT-Code in the FTM partition to match the "82" listed in the file. What could go wrong? I can always restore a backup... After flashing the edited FTM in QFIL, rebooted the phone, and - bingo! The NT-Code error was gone, and the phone was still fully functional. This was my happy face after spending a good hour and a half trying to get rid of it, and finally succeeding: 😁

    Cheers, and thanks again for all the info!
    Thanks, netmsm and kt-froggy for the guides.
    I figured out how to remove the NT code error without root.
    You will first need a file manager that can access the root directory.
    I personally used "Solid Explorer File Manager" to access the cust_path_mapping.cfg file to read the NT-Code that came with the firmware.
    You can use the Solid Explorer File Manager to access the root directory by going to settings then scrolling down and checking the box "show root storage". You will now be able to access the root storage.
    You can access the cust_path_mapping.cfg by going to root/system/product/OP. Then open the file and note the code. Mine was FFFFFF,82=/product/OP.
    Create a backup of the FTM partition the open the FTM file with HxD app. (Make sure you have a copy of the FTM file in case something goes wrong)
    Go to line 00014000 and edit the line. depending on the phone, edit the first 2 sets of numbers/letters with 3 characters separated by a comma. ("FFF,FFF), then the last set of numbers/letters with 2 characters to match the code in the cust_path_mapping.cfg file.
    (Mine was
    "2","310,120,FFFFFFFF,FFFFFFFF,FF","312,530,FFFFFFFF,FFFFFFFF,FF" and I changed to
    "2","FFF,FFF,FFFFFFFF,FFFFFFFF,82","FFF,FFF,FFFFFFFF,FFFFFFFF,82") because I was getting NT code error
    310120, 312530 ; FF, FF

    Note:
    1. The line could span from 00014000 to 00014040 like mine. Each line is separated with "". I had 2 lines and had to change both lines. You can have only 1 line
    2. Make sure you don't delete the line but just select the content and overwrite it with new text. deleting might affect other lines below with content. ( I deleted some lines and my phone factory reset)


    After that just save the FTM and load it to your phone using QFIL and the error will be gone.

    I've only tested it on my LG G8, OPEN CA firmware so I'm not sure if it will work on others.
    6
    Some pictures of flashing my LMG820UM, unlocked from Sprint, into OPEN_CA 20j. In normal mode you cannot flash SPR_US to OPEN_CA which is shown in the pictures. But using this thread instruction it allows to flash, even it asks to change the model from SPR_US to OPEN_CA :D
    Until performing the instructions, it shows the "id: 2(SPR_US)" on the Download Mode screen, but after that it cannot recognize the phone model id and shows "id: 0()" :D
    Have fun ^_^
    5
    Hey good for you, so the Open a11 must be the Kor version right? Either way, could u do a big favor and try to get to recovery? Of course don't erase anything, but just verify you can get to the recovery screen?

    thnx!

    So, we just got this sorted. Thanks to SGMarkus as he mentioned it's the ftm partition that controls recovery access and fastboot access. So, with the newly flashed kdz, as it is, you can't even get to fasboot although u flashed the eng abl to it.

    But! Restore your old ftm, after flashing, and then you'll get access to both recovery and ability to get to fastboot after flashing eng abl.

    cheers!
    4
    First off, big THANKS to the OP (netmsm) and other people who contributed to this thread and made this guide very clear and useful!

    So, after perusing this thread for a long time, trying to understand the ins and outs of the process and any possible snafus, I decided to take the plunge after the Open_CA A12 (40a) got released recently, and to flash it onto my G8 originally from US Cellular. The crossflash went smoothly with no issues at all. A nice surprise was that the BL remained unlocked - I was prepared to go through the whole unlocking process again before rooting, but didn't have to. I got the empty S/N (easy fix), and the infamous NT-Code error. This is where I got stuck for a while. I tried fixing it by editing the cust_path_mapping.cfg file as suggested in the thread. The problem is that I couldn't save the changes in that stupid file by using ANY root explorer/editor! :mad: Tried half a dozen different apps with no luck at all. BTW, anyone has any ideas what I may have been doing wrong?? Yes, I am properly rooted with Magisk.

    Anyway... Everything worked fine on the phone, but that lame error was really getting under my skin - I could have ignored it, but I hated not being able to get rid of it. So... After more reading, I came across some info on hex-editing the FTM partition (in a totally unrelated topic). The NT-Code in FTM binary is stored at the offset 00014000. My error message was referring to the code "FFFFFF,85". The original cust_path_mapping.cfg file (which I couldn't edit) had a line referring to "FFFFFF,82". So, having all backups available, I decided, just for the heck of it, to change the last digits of the NT-Code in the FTM partition to match the "82" listed in the file. What could go wrong? I can always restore a backup... After flashing the edited FTM in QFIL, rebooted the phone, and - bingo! The NT-Code error was gone, and the phone was still fully functional. This was my happy face after spending a good hour and a half trying to get rid of it, and finally succeeding: 😁

    Cheers, and thanks again for all the info!