LG Optimus G E970 stuck in Security Error boot loop

LG Optimus G E970 stuck in Security Error boot loop - LG Optimus G (International)

I rooted my phone, and immediately thereafter I deleted all the AT&T and Google bloatware. I restarted my phone, and now it just goes into an infinite loop:
1) shows the LG logo
2) the screen goes black for a second
3) shows the LG logo with "Security Error" beneath it
4) the screen goes black for a second again
5) and then restarts the process
I have tried doing a hard factory reset from recovery mode (which I enter by holding down the "volume down" and "power" button), but it just boots into the same loop.
I figured my only chance is to access the phone through "download mode", which although I am able to get into in my phone (which I enter by holding down the "volume up" and "volume down" button and then plugging the phone into the computer via USB), Windows 10 won't recognize the ****ing phone. Or rather, it does, but there's an error and I can't actually view any of the phone's files. I am using Windows 10, and below are some pictures (that I can't post cause you need at least 10 posts to do that) showing what Windows is telling me:
- In Device Manager, my phone seems to be under "Universal Serial Bus controllers" and is labeled "USB Composite Device" and and has a yellow warning sign on it.
- If I right click and go to properties, in "Device Status", it says "This device cannot start. (Code 10)".
- In Device and Printers, my phone is under "Devices", but it's labelled as "LG AndroidNet Phone" when I click it once, at the bottom it gives a description of things about the phone, one of them being "Status: Driver error".
I have tried linux mint, but it seems linux won't even recognize it.
I have a also downloaded a few different drivers, but with no luck. I am also aware that the drivers required for "download mode" are different from regular mode.
Thank for reading, and please help, or just say you have to same problem so I don't feel alone

Related

Root Filed- need advice

Hi, I am a Nexus 7 user and was tried to root my device using the Toolkit v1.8.2
I am not experience in rooting Android machine, this was my first time and unsuccessful. My device is now could not be started up.
The following is all information I summarized for this exercise, and would like to seek all advice on the followings.
--1 Is my device "recoverable" if yes, how and what do I need to do please?
--2/ or is it definitely "bricked" so I have no chance to recover it at all.
I am totally in-familiar with rooting machine and I have no access to Linux machine.
Any advice is welcome.
Thx in advance.
Machine: Nexus 7 v2- wifi version Android 4.4.2, Build - KOT49H
Computer: Windows 7 64 bit system
Nexus Root Toolkit v1.8.2
Worked procedure:
1/ Follow the "Initial Setup - Full Driver Installation Guide- Automatic + Manual"
Step 1 to Step 4, install the drivers on the computer. and "Full Driver Test" passed
2/ Click "Unlock", pressed "Y" to proceed. - Device went into a screen asking me to select and confirm, I used the "Vol +" to select "yes" and pressed "power" to confirm, but nothing happened on both computer and device after the "power" switch was pressed. Instead, it freeze the device. nothing is responding even after 10 minutes.
3/ I have pressed the "power button again for 5 sec. and device shutdown to black screen.
4/ Since then, every time I try to start the device, the machine first show a "Google" , then a "rotating flower pattern" and won't started. i.e. - "the flower pattern" keeps looping.
5/ on the computer side, no matter what command is given in Nexus Root Toolkit, a notification of ADB device was not found error comes up.
Consequence
A) Device can be switched on and off by pressing "power" button. when switch on, it display "Google" , then a rotating flower pattern, and never end.
Switch the power button for 5 sec again, device switch off.
B) When device is off, press 'power' and "vol -" will switch on the device to a menu with a robot lay down, options "Restart bootloader", "Recovery mode", "Power off" and "Start" can be selected.
C) For "restart bootloader" the screen goes black for 2 sec, then the menu appear again with "Start" option. i.e.- no error no message
D) For "Start " - the device just just act like normal start, end up in a looping rotating flower pattern.
E) For " Recovery mode" - device screen goes black for 3 sec. show "Google" then show a dead robot with an exclamation mark on it, message " No command" is showing. - After awhile, device restarted and end up in the rotating flower pattern.
F) When plugged in, Window 7 can detect the device, when teh device is in the menu, "Android Bootloader Interface" is shown in Windows Device manager, when the device is starting, " Nexus 7" is detected in Windows Device manager but not both.Hi, I am a Nexus 7 user and was tried to root my device using the Toolkit v1.8.2
I am not experience in rooting Android machine, this was my first time and unsuccessful. My device is now could not be started up.
The following is all information I summarized for this exercise, and would like to seek all advice on the followings.
--1 Is my device "recoverable" if yes, how and what do I need to do please?
--2/ or is it definitely "bricked" so I have no chance to recover it at all.
I am totally in-familiar with rooting machine and I have no access to Linux machine.
Any advice is welcome.
Thx in advance.
Machine: Nexus 7 v2- wifi version Android 4.4.2, Build - KOT49H
Computer: Windows 7 64 bit system
Nexus Root Toolkit v1.8.2
Worked procedure:
1/ Follow the "Initial Setup - Full Driver Installation Guide- Automatic + Manual"
Step 1 to Step 4, install the drivers on the computer. and "Full Driver Test" passed
2/ Click "Unlock", pressed "Y" to proceed. - Device went into a screen asking me to select and confirm, I used the "Vol +" to select "yes" and pressed "power" to confirm, but nothing happened on both computer and device after the "power" switch was pressed. Instead, it freeze the device. nothing is responding even after 10 minutes.
3/ I have pressed the "power button again for 5 sec. and device shutdown to black screen.
4/ Since then, every time I try to start the device, the machine first show a "Google" , then a "rotating flower pattern" and won't started. i.e. - "the flower pattern" keeps looping.
5/ on the computer side, no matter what command is given in Nexus Root Toolkit, a notification of ADB device was not found error comes up.
Consequence
A) Device can be switched on and off by pressing "power" button. when switch on, it display "Google" , then a rotating flower pattern, and never end.
Switch the power button for 5 sec again, device switch off.
B) When device is off, press 'power' and "vol -" will switch on the device to a menu with a robot lay down, options "Restart bootloader", "Recovery mode", "Power off" and "Start" can be selected.
C) For "restart bootloader" the screen goes black for 2 sec, then the menu appear again with "Start" option. i.e.- no error no message
D) For "Start " - the device just just act like normal start, end up in a looping rotating flower pattern.
E) For " Recovery mode" - device screen goes black for 3 sec. show "Google" then show a dead robot with an exclamation mark on it, message " No command" is showing. - After awhile, device restarted and end up in the rotating flower pattern.
F) When plugged in, Window 7 can detect the device, when teh device is in the menu, "Android Bootloader Interface" is shown in Windows Device manager, when the device is starting, " Nexus 7" is detected in Windows Device manager but not both.

chanwt12000 said:
Hi, I am a Nexus 7 user and was tried to root my device using the Toolkit v1.8.2
I am not experience in rooting Android machine, this was my first time and unsuccessful. My device is now could not be started up.
The following is all information I summarized for this exercise, and would like to seek all advice on the followings.
--1 Is my device "recoverable" if yes, how and what do I need to do please?
--2/ or is it definitely "bricked" so I have no chance to recover it at all.
I am totally in-familiar with rooting machine and I have no access to Linux machine.
Any advice is welcome.
Thx in advance.
Machine: Nexus 7 v2- wifi version Android 4.4.2, Build - KOT49H
Computer: Windows 7 64 bit system
Nexus Root Toolkit v1.8.2
Worked procedure:
1/ Follow the "Initial Setup - Full Driver Installation Guide- Automatic + Manual"
Step 1 to Step 4, install the drivers on the computer. and "Full Driver Test" passed
2/ Click "Unlock", pressed "Y" to proceed. - Device went into a screen asking me to select and confirm, I used the "Vol +" to select "yes" and pressed "power" to confirm, but nothing happened on both computer and device after the "power" switch was pressed. Instead, it freeze the device. nothing is responding even after 10 minutes.
3/ I have pressed the "power button again for 5 sec. and device shutdown to black screen.
4/ Since then, every time I try to start the device, the machine first show a "Google" , then a "rotating flower pattern" and won't started. i.e. - "the flower pattern" keeps looping.
5/ on the computer side, no matter what command is given in Nexus Root Toolkit, a notification of ADB device was not found error comes up.
Consequence
A) Device can be switched on and off by pressing "power" button. when switch on, it display "Google" , then a rotating flower pattern, and never end.
Switch the power button for 5 sec again, device switch off.
B) When device is off, press 'power' and "vol -" will switch on the device to a menu with a robot lay down, options "Restart bootloader", "Recovery mode", "Power off" and "Start" can be selected.
C) For "restart bootloader" the screen goes black for 2 sec, then the menu appear again with "Start" option. i.e.- no error no message
D) For "Start " - the device just just act like normal start, end up in a looping rotating flower pattern.
E) For " Recovery mode" - device screen goes black for 3 sec. show "Google" then show a dead robot with an exclamation mark on it, message " No command" is showing. - After awhile, device restarted and end up in the rotating flower pattern.
F) When plugged in, Window 7 can detect the device, when teh device is in the menu, "Android Bootloader Interface" is shown in Windows Device manager, when the device is starting, " Nexus 7" is detected in Windows Device manager but not both.Hi, I am a Nexus 7 user and was tried to root my device using the Toolkit v1.8.2
I am not experience in rooting Android machine, this was my first time and unsuccessful. My device is now could not be started up.
The following is all information I summarized for this exercise, and would like to seek all advice on the followings.
--1 Is my device "recoverable" if yes, how and what do I need to do please?
--2/ or is it definitely "bricked" so I have no chance to recover it at all.
I am totally in-familiar with rooting machine and I have no access to Linux machine.
Any advice is welcome.
Thx in advance.
Machine: Nexus 7 v2- wifi version Android 4.4.2, Build - KOT49H
Computer: Windows 7 64 bit system
Nexus Root Toolkit v1.8.2
Worked procedure:
1/ Follow the "Initial Setup - Full Driver Installation Guide- Automatic + Manual"
Step 1 to Step 4, install the drivers on the computer. and "Full Driver Test" passed
2/ Click "Unlock", pressed "Y" to proceed. - Device went into a screen asking me to select and confirm, I used the "Vol +" to select "yes" and pressed "power" to confirm, but nothing happened on both computer and device after the "power" switch was pressed. Instead, it freeze the device. nothing is responding even after 10 minutes.
3/ I have pressed the "power button again for 5 sec. and device shutdown to black screen.
4/ Since then, every time I try to start the device, the machine first show a "Google" , then a "rotating flower pattern" and won't started. i.e. - "the flower pattern" keeps looping.
5/ on the computer side, no matter what command is given in Nexus Root Toolkit, a notification of ADB device was not found error comes up.
Consequence
A) Device can be switched on and off by pressing "power" button. when switch on, it display "Google" , then a rotating flower pattern, and never end.
Switch the power button for 5 sec again, device switch off.
B) When device is off, press 'power' and "vol -" will switch on the device to a menu with a robot lay down, options "Restart bootloader", "Recovery mode", "Power off" and "Start" can be selected.
C) For "restart bootloader" the screen goes black for 2 sec, then the menu appear again with "Start" option. i.e.- no error no message
D) For "Start " - the device just just act like normal start, end up in a looping rotating flower pattern.
E) For " Recovery mode" - device screen goes black for 3 sec. show "Google" then show a dead robot with an exclamation mark on it, message " No command" is showing. - After awhile, device restarted and end up in the rotating flower pattern.
F) When plugged in, Window 7 can detect the device, when teh device is in the menu, "Android Bootloader Interface" is shown in Windows Device manager, when the device is starting, " Nexus 7" is detected in Windows Device manager but not both.
Click to expand...
Click to collapse
http://forum.xda-developers.com/attachment.php?attachmentid=2741375&stc=1&d=1399986292
http://forum.xda-developers.com/attachment.php?attachmentid=2741374&stc=1&d=1399986292
http://forum.xda-developers.com/attachment.php?attachmentid=2741373&stc=1&d=1399986292

I'll take up the task to help you. You are not bricked. You are stuck in something called a bootloop, which is basically when the device enters the boot sequence, but never finishes. The flower pattern that you are looking at us called the boot animation. The computer never recoginizes the tablet through ADB because the tablet never gets to that point.
The screen with the Android laying on his back is actually the bootloader itself. That's why restarting the bootloader brings you to the same screen. I actually want you to be in the bootloader screen. You already have the Nexus 7.2 drivers, so you're ahead of the game.
You also need to visit here to download TWRP 2.7. You also need to put the file in the same directory as the fastboot and adb files.
You need to boot into the bootloader, and run the command:
fastboot flash recovery <recoveryname>.img
This should get TWRP onto your device. You can then download a rom of your choice to put on the tablet. Since you will not have access to place files on the device through USB, you will have to sideload it. First, let's get recovery working, then come back to me if you need help sideloading the rom through ADB while in recovery.

Dear aarsyl,
Thx for your help and it is much better to know my device is not "bricked". Thx again!
Thx for your detailed explaination and I feel much better by knowing a little bit more on what is going on.
>>>>You also need to visit here to download TWRP 2.7. You also need to put the file in the same directory as the fastboot and adb files.
[I also found it in my computer already .\WugFresh Development\data\Recovery_Custom\TWRP
but I downlaod it again from your link and put this file in the same directory where I find the fastboot.exe and adb.exe, which in my case is .\WugFresh Development\data\ ------ done.]
>>>>You need to boot into the bootloader, and run the command:
[- I supose you refer to my Nexus 7, so I will switch it on with the "power button + vol -" button. and get it into the bootloader.]
>>>>fastboot flash recovery <recoveryname>.img
[Here I got an query, what image file I need to use? is it the <openrecovery-twrp-2.7.0.0-flo> ? Do I neeed to run it as an adminstartor in Window 7?
so, do u mean I need to type: fastboot flash recovery openrecovery-twrp-2.7.0.0-flo.img ?
is it right?--(A)
if not, then I am not sure what recovery file to be used!
I do not have any other img file in package I downloaded previously
>>>>This should get TWRP onto your device. You can then download a rom of your choice to put on the tablet. Since you will not have access to place files on the device through USB, you will have to sideload it. First, let's get recovery working, then come back to me if you need help sideloading the rom through ADB while in recovery.
Not quite understand it this bit, but as you say. it can wait later.
So assume I do the "fastboot flash recovery <recoveryname>.img and get the TWRP on the Nexus 7.
What do I expect to see from the nexus screen. Does it have any note saying completed, or shuold I expect a reboot of the Nexus.
I think one of the problem dealing with these kind of thing is lack of acknowledgment fromt eh machine so we do not know if the operation is successful or not.

chanwt12000 said:
Dear aarsyl,
Thx for your help and it is much better to know my device is not "bricked". Thx again!
Thx for your detailed explaination and I feel much better by knowing a little bit more on what is going on.
>>>>You also need to visit here to download TWRP 2.7. You also need to put the file in the same directory as the fastboot and adb files.
[I also found it in my computer already .\WugFresh Development\data\Recovery_Custom\TWRP
but I downlaod it again from your link and put this file in the same directory where I find the fastboot.exe and adb.exe, which in my case is .\WugFresh Development\data\ ------ done.]
>>>>You need to boot into the bootloader, and run the command:
[- I supose you refer to my Nexus 7, so I will switch it on with the "power button + vol -" button. and get it into the bootloader.]
>>>>fastboot flash recovery <recoveryname>.img
[Here I got an query, what image file I need to use? is it the <openrecovery-twrp-2.7.0.0-flo> ? Do I neeed to run it as an adminstartor in Window 7?
so, do u mean I need to type: fastboot flash recovery openrecovery-twrp-2.7.0.0-flo.img ?
is it right?--(A)
if not, then I am not sure what recovery file to be used!
I do not have any other img file in package I downloaded previously
>>>>This should get TWRP onto your device. You can then download a rom of your choice to put on the tablet. Since you will not have access to place files on the device through USB, you will have to sideload it. First, let's get recovery working, then come back to me if you need help sideloading the rom through ADB while in recovery.
Not quite understand it this bit, but as you say. it can wait later.
So assume I do the "fastboot flash recovery <recoveryname>.img and get the TWRP on the Nexus 7.
What do I expect to see from the nexus screen. Does it have any note saying completed, or shuold I expect a reboot of the Nexus.
I think one of the problem dealing with these kind of thing is lack of acknowledgment fromt eh machine so we do not know if the operation is successful or not.
Click to expand...
Click to collapse
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
I decided to have a go with the downloaded twrp img file.
I launched the command " fastboot flash recovery openrecovery-twrp-2.7.0.0-flo.img" from a command window as an adminstrator.
The command failed with an error saying (remote: Bootloader is locked)
And when I check the Nexus 7 screen, it does said "Locked Status - locked" in the last line.
photo showing both the computer and teh Nexus 7 screen.

Oh, I hadn't realized that you were still locked. No wonder you're not getting anywhere.
Reboot into the bootloader, and run:
fastboot oem unlock
Follow the screen instructions to unlock the bootloader, then run the command to flash the recovery. I advise changing the recovery name to something shorter and simpler, like twrp27flo.img, for example.

aarsyl said:
Oh, I hadn't realized that you were still locked. No wonder you're not getting anywhere.
Reboot into the bootloader, and run:
fastboot oem unlock
Follow the screen instructions to unlock the bootloader, then run the command to flash the recovery. I advise changing the recovery name to something shorter and simpler, like twrp27flo.img, for example.
Click to expand...
Click to collapse
Hi, Nice to have reply from you again.
Ammm. I switch on the device to the bootloader alright. run teh command "fastboot oem unlock"
On teh command window, it said" < waiting for device>
and there is no visible change on the device screen.
It already last for 10 minutes now.
I do noted that both windows are freezed and do not respond to key press and button press respectively. No responds on both the device and computer.
How lond does this process take to show the mentioned "screen instruction"? I don't see one!

chanwt12000 said:
Hi, Nice to have reply from you again.
Ammm. I switch on the device to the bootloader alright. run teh command "fastboot oem unlock"
On teh command window, it said" < waiting for device>
and there is no visible change on the device screen.
It already last for 10 minutes now.
I do noted that both windows are freezed and do not respond to key press and button press respectively. No responds on both the device and computer.
How lond does this process take to show the mentioned "screen instruction"? I don't see one!
Click to expand...
Click to collapse
wow.. it is unlocked now!
Should I continue to use the "fastboot recover command with TWRP file" as per your advise or should I continue to use the "Root" command in NexusRoot Toolkit ??
It is very happy to see there is progress.. Thx...
please keep coming...

I would go with using fastboot to install TWRP. In truth, to truly "root" your device, you actually need a working rom on the device. Otherwise, rooting will be in vain. Unlocking the device was the most important.

aarsyl said:
I would go with using fastboot to install TWRP. In truth, to truly "root" your device, you actually need a working rom on the device. Otherwise, rooting will be in vain. Unlocking the device was the most important.
Click to expand...
Click to collapse
Hi again,
Yes. my device is now boot up as brand new.
One side observation though, every time I issue command through window 7 in a command window, everything will freeze up, (not remember if I unplugged the device) until I press the power button to restart the Nexus 7. Same for the last time when i did the unlock and this time recovery.
The hesitation was how do I know when to do this, was worrying there is still some communication between the two machines if I unplug or interfer, may just disturb the communication and corrupt files. -- I normally give it some 10 minutes before I do the unplug and restart. any comment or advice?
Anyway, the device is now up and running. What is the status now? is it with the original version of software? or TWRP version or what?
The device is now remain "unlocked" - is it ok or I need to lock it again?
You have mentioned to download a "Rom", what about it, it is only need if i want to continue to "root " the device?
Sorry for so much question.
I am so happy to see it comes alive again but really would like to understand the current status of it.
Thank again. aarsyl

To be honest, I'm not entirely sure what the status of your device is right now. I was under the implication that you had no Rom on the device. Since you are trying to root for the first time, then yes, you are on the stock software that comes with the device. If you search your app drawer and find the SuperSU app, then you are already rooted, my friend. If it is not there, then search for SuperSU 1.94 in Google, and download the zip file. Then reboot into recovery and flash it.
In other news, I am happy that you got your device working, and I am more than happy to help. The only thing that I don't do is recommend roms. I encourage users to explore different roms for themelves.

[b]AarSyl[/b] said:
To be honest, I'm not entirely sure what the status of your device is right now. I was under the implication that you had no Rom on the device. Since you are trying to root for the first time, then yes, you are on the stock software that comes with the device.>>> since you mentioned I probably have no rom on the device...and you also mentioned "stock software with my device"..I think these are 2 different things right? because i always thought they are the same thing.
If you search your app drawer and find the SuperSU app, >>>App drawer, do you refer to the Apps Tab under Setting? I don't have SuperSU in there.
then you are already rooted, my friend. If it is not there, then search for SuperSU 1.94 in Google, and download the zip file.
Then reboot into recovery and flash it. >>>>I have to say you lost me, do u mean use the ""fastboot flash recovery <Super SU file>.img" command?
In other news, I am happy that you got your device working, and I am more than happy to help. The only thing that I don't do is recommend roms. I encourage users to explore different roms for themelves.>>>No problem, I shall be looking out for that
Click to expand...
Click to collapse
Well, sure I will continues to look up the information from the basic, but at the moment Would you please enlight me for the following 2 questions
1/ Should I uncheck or check the USB debugging tab under Developer options - it will be very good if you would like to explain a little on what it does, so I will have a more l\idea what it does when when do i need them.
2/ As i said, teh device is now unlocked, is it ok to leave it unlock or should i have it lock? - again if you would explain a little more on this that will be marvest.
cheers

chanwt12000 said:
Well, sure I will continues to look up the information from the basic, but at the moment Would you please enlight me for the following 2 questions
1/ Should I uncheck or check the USB debugging tab under Developer options - it will be very good if you would like to explain a little on what it does, so I will have a more l\idea what it does when when do i need them.
2/ As i said, teh device is now unlocked, is it ok to leave it unlock or should i have it lock? - again if you would explain a little more on this that will be marvest.
cheers
Click to expand...
Click to collapse
I'm sorry for the long delay. I got locked out trying to log in after I changed my username twice, and it just got messy for me. At any rate....the SuperSU zip file is to be flashed through recovery. When you boot into recovery, select Install, then navigate through the device to find the folder that the file is located. Follow the screen directions to flash items.
USB Debugging needs to be checked for ADB to work, so.....yeah....leave it on.
You don't have to relock your device unless you have to bring it back to the store for repairs. It only stops you from making changes in the bootloader, such as flashing new recoveries, and I think that most fastboot commands might be blocked. I have never tried to use fastboot on a locked device, so I really don't know. Leaving the device unlocked doesn't make it vulnerable or anything, at least to my knowledge.

AarSyl said:
I'm sorry for the long delay. I got locked out trying to log in after I changed my username twice, and it just got messy for me. At any rate....the SuperSU zip file is to be flashed through recovery. When you boot into recovery, select Install, then navigate through the device to find the folder that the file is located. Follow the screen directions to flash items.
USB Debugging needs to be checked for ADB to work, so.....yeah....leave it on.
You don't have to relock your device unless you have to bring it back to the store for repairs. It only stops you from making changes in the bootloader, such as flashing new recoveries, and I think that most fastboot commands might be blocked. I have never tried to use fastboot on a locked device, so I really don't know. Leaving the device unlocked doesn't make it vulnerable or anything, at least to my knowledge.
Click to expand...
Click to collapse
Thx for your advices AarSyl,
I have successfully root the device and get the Super user app running by following one of tutorial video.
For the first time, when I start at teh bootloader and conduct a "Recovery", it shows a dead robot again but without "no command". I have to redo the fastboot command in the command window with the TWRP recovery file once again. (but this time is very smooth no need to unplug cable that sorts of thing) then I get into the TWRP menu after "Recovery".

chanwt12000 said:
Thx for your advices AarSyl,
I have successfully root the device and get the Super user app running by following one of tutorial video.
For the first time, when I start at teh bootloader and conduct a "Recovery", it shows a dead robot again but without "no command". I have to redo the fastboot command in the command window with the TWRP recovery file once again. (but this time is very smooth no need to unplug cable that sorts of thing) then I get into the TWRP menu after "Recovery".
Click to expand...
Click to collapse
Great. I'm happy that it is working for you. A little tip...download Quick Boot from the Play Store. With one touch, you can power off, boot into the bootloader, boot into recovery, or reboot Android.

[Q] Unable boot to "Download mode"

Hi every one
i got my E988 OTA update , but it fail to boot up and Show "secure booting error cause boot certification verify"
i tried many method on this forum , but it not enter "Download Mode" and detect by the PC. Please advise anything i can try?
Thank you everyone :crying:

Make sure your drivers are installed.. Take battery out and hold both volume buttons and plug in usb
2SHAYNEZ

It took me a while as well to figure out the whole 'Download Mode' thing but it became easier once I got the technique down. This is my anecdotal evidence but I dont think you need to surely have drivers installed since I plugged it into my Linux machine and it still entered download mode.
This is the method I used.
1) Turn the device completely off.
2) With one hand, Hold down both Volume arrows on the device for about 3 seconds
3) Using your other hand, plug your device into your computer. (As in, already have it plugged into USB and plug the Micro-USB port into your phone)
4) And it should show 'Download Mode' on your phone.
Hope that helps!

Thank you all bro~
 @shayneflashindaily thank you ~I have install/reinstall every Driver,and also got same..
 @GreatCaesar: i tried your method , it got same result , still show "secure booting error":crying:

maybe its a bad cable.......

another bricked 851

I upgraded to D85120g via the LG Mobile Support Tool but lost root. While trying to restore root access, I bricked my device. Its stuck on the opening splash screen. The power button does not appear to be active. The notification led cycles between green/blue/off.
Typing "adb reboot recovery" in a console window says, "error: device not found".
The LG Mobile Support Tool recognizes the phone and says it has Software Version: D85120G, the latest available. If I click 'Options', then 'Upgrade Recovery', it goes through the steps of verifying windows, downloading 1226.54 MBytes, software extraction, and S/W Upgrade. But it only gets 4% through the upgrade and then says, "Upgrade stopped due to an error."
Powering up the phone while pressing the volume down, releasing when the splash first shows, then holding the power button again brings up the Factory data reset. I tell it yes to erase all user data & restore default settings, then yes to start. It immediately goes to the splash screen, then then android robot appears and says erasing for about 1 second, then the splash screen again. That's the last it does.
The phone shows up as a serial port but the drive letter it was mapped to has a yellow triangle "!" in device manager and says device can't start.
Can I get my phone to work again?

Got it working!
The trick was to manually set the phone into download mode by holding the volume up with the power off, then connecting to the usb cable. Once in download mode, I started LG Mobile Support Tool, clicked Options, then Install Recovery. It went through the complete process. I lost all my data but saved the phone!
Now I need root back.

LG G3 in download mode not detected by Windows

Dear xda-developers-community,
I'm trying to get a phone of a friend of mine working which just reboots whenever the phone is started. The resulting boot loop can only be interrupted by taking the battery out or wait until it is depleeted.
In order to fix this soft-brick I first tried to use recovery by pressing VOL - & POWER. In the menu, I could select and confirm to recover to factory settings, but after some seconds the boot loop appeared again with (seemingly?) no change having been made. The error kept appeaing over and over again.
After trying recovery mode, I attempted to start the phone in download mode by pressing VOL + on the (switched off) phone and connecting a USB cable. The respective menu also opened, here, showing "Firmware Update" and "Do not unplug the USB connection until the process is complete". According to many tutorials I found on the internet, when having installed the required drivers (I used LG United Mobile drivers from here), this procedure should allow you to flash a recovery image through LG's flashing tool (which one can also find on that page).
However, when I connect the LG G3 (D855) to a computer the driver is installed on, there is no new device shown in the Device manager. I tried this out with Windows 10 x64 and Windows 7 x64 and disabled driver validation on both systems and enabled test signing on Windows 10, respectively. Additionally, I followed these instructions, but in this case the screen stays dark and the device is not detected either. It seems like there are not so many people experiencing this error, but I hope we can find a solution.

nVentis said:
Dear xda-developers-community,
I'm trying to get a phone of a friend of mine working which just reboots whenever the phone is started. The resulting boot loop can only be interrupted by taking the battery out or wait until it is depleeted.
Click to expand...
Click to collapse
This may sound like a dumb question, but have you tried a new battery yet? If it is one of the original batteries it could have gone bad & started bootlooping...like mine did a few months ago.
As far as the PC not recognizing the phone you can try downloading USBDeview and uninstall anything that has the vendor ID's of 1004 & 18d1(pretty much anything that says android or LGE in the description) & reboot the PC. Hopefully it'll recognize your device and install the drivers the next time you plug it in. If it doesn't find the drivers automatically for you then install LG drivers manually.
Link for usbdeview: http://www.nirsoft.net/utils/usb_devices_view.html
Link for LGE drivers: http://www.lg.com/us/support/software-firmware-drivers
Good luck :fingers-crossed:

Bricked my LGG3

Hello everyone,
so here's my problem:
Wednesday morning i took my phone out of my pocket and had a blackscreen. I tried to restart it and took out the batterie but i always got stuck in the LG Logo or a bootloop. Since i had TWRP and lineage OS installed, i tried to go into the twrp menu with the factory mode (power button + volume down) but after the "double yes" i always got a blackscreen.
So i went into the internet to fix it myself. I tried the "LG Flash Tool 2014" with the kdz. reset & the other Flash tool with the tot. reset. Both didnt recognize my phone. At this point, the only thing that worked was the download mode BUT not the recovery mode that usually comes after it. It just showed the download mode for some seconds and then a black screen. Later i noticed that my phone showed as a "qualcomm device" in the device manager, and the internet said that this was bad. So i used "Board diag" and "Smart boot diag" to fix it, but at the point where the device should have restarted, and the download mode should have worked WITH the recovery mode, i always ONLY had the 6 second download mode. After messing a bit with "Board Diag" i even got it to show up as LGE AndroidNet USB Serial Port in the device manager, which apparently was even more bad and only way to go back to qualcomm was to shorten the pins which i did. And it worked BUT now i was back with the qualcomm stuff.
So as you can see, i've prety much run i circles since wednesday... Iam now at a point where 3 different thingscan happen when I try to put my LG into download mode (volume up + usb cable):
1. Its recognized as a unknown device which is constantly connecting and diconnecting, so iam assuming my phone is bootlooping with a black screen.
2. The download mode icon shows on my phone and disappears after some seconds but my pc fails to recognize it.
3. Nothing happens and the screen stays black
When i only connect the usb cable, it shows a stuck charging icon for some seconds and then goes black. Connecting without a battery shows the "missing battery icon". I tried with 2 pc's, both having the LG mobile driver 4.2 and the qualcomm driver installed AND beeing in testmode. Both don't recognize the device. I also tried 2 batteries on my phone but it changes nothing.
I have a D855. And i know that my situation is pretty f*cked but maybe someone i able to help me anyway. Thanks alot.

Develop Bugs

welcome