LG G7 - Fastboot bootloop [SOLVED]

Prosjak

Member
Dec 11, 2013
6
2
0
After trying to flash Pie my G7 stuck in fastboot mode. Download mode is unavailable so I not can reset the stock ROM.
After it reboots it boots into only to fastboot mode and is stuck in a loop now.

An even bigger problem is that now the bootloader is locked and the unlock.bin file can not unlock the bootloader.

ADB mode is not working!
DOWNLOAD mode is not working!
SYSTEM mod does not work!

There is only FASTBOOT mode that is in the loop

Does anyone have any suggestions?
 
Last edited:
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Joe199799

Senior Member
Sep 7, 2014
825
281
93
After trying to flash Pie my G7 stuck in fastboot mode. Download mode is unavailable so I not can reset the stock ROM.
After it reboots it boots into only to fastboot mode and is stuck in a loop now.

An even bigger problem is that now the bootloader is locked and the unlock.bin file can not unlock the bootloader.

ADB mode is not working!
DOWNLOAD mode is not working!
SYSTEM mod does not work!

There is only FASTBOOT mode that is in the loop

Does anyone have any suggestions?

Try to get into lgup to flash a kdz, if you cant do that you might be SOL
 

LameMonster82

Senior Member
Apr 15, 2017
583
318
0
After trying to flash Pie my G7 stuck in fastboot mode. Download mode is unavailable so I not can reset the stock ROM.
After it reboots it boots into only to fastboot mode and is stuck in a loop now.

An even bigger problem is that now the bootloader is locked and the unlock.bin file can not unlock the bootloader.

ADB mode is not working!
DOWNLOAD mode is not working!
SYSTEM mod does not work!

There is only FASTBOOT mode that is in the loop

Does anyone have any suggestions?
Fastboot --set-active=a
 

Prosjak

Member
Dec 11, 2013
6
2
0
Problem solved

Octoplus/Octopus LG 2.9.3

Reset FRP Lock
1. Attach testpoint, and connect phone with Micro USB cable (don´t use USB hubs!).
2. Check PC Device Manager, a new device should appear "Qualcomm HS-USB QDLoader 9008" or "Unknown Device" if you hadn´t installed a driver.
3. Release testpoint and press "Reset FRP Lock" button.

Emergency mode
To enter emergency mode, disconnect cable, disconnect battery, press and hold "Vol+" button and connect USB cable.

My lucky day :eek:;)
 

Wilmer25

New member
Apr 5, 2016
4
0
0
Octoplus/Octopus LG 2.9.3

Reset FRP Lock
1. Attach testpoint, and connect phone with Micro USB cable (don´t use USB hubs!).
2. Check PC Device Manager, a new device should appear "Qualcomm HS-USB QDLoader 9008" or "Unknown Device" if you hadn´t installed a driver.
3. Release testpoint and press "Reset FRP Lock" button.

Emergency mode
To enter emergency mode, disconnect cable, disconnect battery, press and hold "Vol+" button and connect USB cable.

My lucky day :eek:;)
how i can do this?
 

凄夜守护

New member
Jul 10, 2017
2
0
0
My G710EM has a problem with my lockback BL. I can't boot the system and it will prompt "Your device has failed a routine safety check and will not boot. This may be a temporary problem. If this message occurs repeatedly, visit this link on Another device and refer to the red case:g.co/ABH Your device will power off automatically after a while.” With LGup brush kdz brush does not go in, fastboot “fastboot flash unlock unlock.bin” prompt is invalid
* Target reported max download size of 536870912 bytes
Sending 'unlock' (1 KB)...
OKAY [ 0.004s]
Writing 'unlock'...
FAILED (remote: Flashing Unlock is not allowed
)
Finished. total time: 0.011s

I don't know what to do.
 

Garlikus

Member
Jun 23, 2019
5
6
0
I had the very same problem as OP. I tried to install pie with LGUP (G710EM20b_00_OPEN_EU_OP_0508.kdz) but ended in fastboot loop.
After whole night of trying different things (being a noob means less sleep) I managed to run the phone in download mode. Starting from there I was able to install my previous rom. Both failed update and rescue operations were done on Win 10.

What I tried and didn't work:
- Fastboot --set-active=a
Code:
C:\ADB>Fastboot --set-active=a
Setting current slot to 'a'...
FAILED (remote: Slot Change is not allowed in Lock State)
finished. total time: 0.003s
- Unlocking with unlock.bin. Didn't save the msg but saw it somewhere in another thread. I needed to install/point drivers first because the device was not recognized in Win.
- Solutions for G6 for going into download mode. The download mode icon was displayed for a second and then going to fastboot again.
- LG Flash Tool 2014 - I just followed a guide for older phones but it didn't work. Didn't try again.

What did work:
1. I found this post on reddit (remove spaces or PM me, I'm not allowed to post links):
Code:
https:// www .reddit. com/r/LGG3/comments/2qe5sr/in_need_of_serious_help_stuck_in_fastbootno/cn5f2qr/?utm_source=share&utm_medium=web2x
Quoting the post
At first, you'll need a working fastboot environment, you'll find out how to set it up on your own. Then you'll need the laf.img, I can upload mine if you want or I could help you extracting one out of a kdz file. Put the laf.img in the same folder like your fastboot.exe, then hold shift and right click, then click on "open command panel here" or however it's called in English. Type "fastboot flash laf laf.img" (Edit: It would probably better to use "fastboot boot laf.img" instead because of the bootloader lock). If that works, you at least have a working download mode.
2. I used LG_Firmware_Extract_v1.2.6.1 and extracted dz file from aforementioned pie file. The I extracted two laf files for the kz file. In my case they were: laf.img_180534 and laf.img_81990.
3. I took one of these files (sry, don't remember which one, but they have the same size - didn't check if they're the same) renamed it to laf.img and put a folder where fastboot.exe is.
4. I did
Code:
fastboot boot laf.img
and voila: the phone was in download mode!
5. After that LGUP the previous rom and the phone is working again. Here I needed few tries. At first the were some problems, then I tried different combinations (1.14, 1.15, w/ and w/o uppercut). I think LGUP 1.15 (1.14 with patch) did the work. I was able to "refurbish" the phone.

Hope it's useful for others. If anyone could prepare a guide from this description or/and tell why it worked - please feel free to do so.

I think I will wait some time before trying pie again :)
 
Last edited:

davinik84

New member
Nov 26, 2010
4
0
0
I had the very same problem as OP. I tried to install pie with LGUP (G710EM20b_00_OPEN_EU_OP_0508.kdz) but ended in fastboot loop.
After whole night of trying different things (being a noob means less sleep) I managed to run the phone in download mode. Starting from there I was able to install my previous rom. Both failed update and rescue operations were done on Win 10.

What I tried and didn't work:
- Fastboot --set-active=a
Code:
C:\ADB>Fastboot --set-active=a
Setting current slot to 'a'...
FAILED (remote: Slot Change is not allowed in Lock State)
finished. total time: 0.003s
- Unlocking with unlock.bin. Didn't save the msg but saw it somewhere in another thread. I needed to install/point drivers first because the device was not recognized in Win.
- Solutions for G6 for going into download mode. The download mode icon was displayed for a second and then going to fastboot again.
- LG Flash Tool 2014 - I just followed a guide for older phones but it didn't work. Didn't try again.

What did work:
1. I found this post on reddit (remove spaces or PM me, I'm not allowed to post links):
Code:
https:// www .reddit. com/r/LGG3/comments/2qe5sr/in_need_of_serious_help_stuck_in_fastbootno/cn5f2qr/?utm_source=share&utm_medium=web2x
Quoting the post
2. I used LG_Firmware_Extract_v1.2.6.1 and extracted dz file from aforementioned pie file. The I extracted two laf files for the kz file. In my case they were: laf.img_180534 and laf.img_81990.
3. I took one of these files (sry, don't remember which one, but they have the same size - didn't check if they're the same) renamed it to laf.img and put a folder where fastboot.exe is.
4. I did
Code:
fastboot boot laf.img
and voila: the phone was in download mode!
5. After that LGUP the previous rom and the phone is working again. Here I needed few tries. At first the were some problems, then I tried different combinations (1.14, 1.15, w/ and w/o uppercut). I think LGUP 1.15 (1.14 with patch) did the work. I was able to "refurbish" the phone.

Hope it's useful for others. If anyone could prepare a guide from this description or/and tell why it worked - please feel free to do so.

I think I will wait some time before trying pie again :)
Thanks for you guide.. I follow it but unfortunatly after "fastboot boot laf.img" I get this message from my LG:

"Your device has failed a routine safety check.... it will reboot after a while.."
 

Garlikus

Member
Jun 23, 2019
5
6
0
Thanks for you guide.. I follow it but unfortunatly after "fastboot boot laf.img" I get this message from my LG:

"Your device has failed a routine safety check.... it will reboot after a while.."
I recall I also had some error msg, it could've been the same. Now I don't remember what I exactly did next as most my actions were more or less random. Either I tried the same command but with other laf.img file (from the rom I used before), or I tried to restart the phone into download mode (vol- and power together and then vol+ after screen goes black) or tried the same file again.
Hope it helps.
 

Garlikus

Member
Jun 23, 2019
5
6
0
I have the same problem as well. I follow the guide but I received the same error message
Check if the phone is recognized in LG Bridge. If so, then choose update error recovery from software update tab. Again, I don't remember if it worked immediately or did I need to reinstall drivers and/or choose a proper driver in device manager (generic ADB vs LG...) and/or restart the phone.
 

Garlikus

Member
Jun 23, 2019
5
6
0
I have same error too ...
Based on other threads, e.g. https://forum.xda-developers.com/v20/how-to/restore-v20-to-100-stock-bricked-devices-t3524903 and https://www.reddit.com/r/lgg6/comments/axd17d/lg_g6_eu_glh870_bricked_after_update_your_device/
try:
install the LG Bridge updater software on a computer, go to updates, click the "correct update errors" button. Then plug in your turned-off phone while holding down the volume up button. It should switch to download mode and reinstall all software from the PC. Yes, this will erase all data but it should unbrick your phone (unless the hardware's broken I guess)