[Q] Bootloader Problem - LG Optimus 4X HD

Hello,
've got a little problem hope you can help me with this.
I have since 2 months my LG 4X HD and I've now decided to root it and unlock the bootloader. Got no problems with the root (did it with the AIO-Tool). When I tried to unlock the bootloader I realized that the AIO tool is only for versions EUR-XXX-& some 262-000. But since I live in Austria, and thus have the version 232-10, it would not work. That's why I first tried the app "Unlock".
While trying this I received error message "Unlock doesn't work anymore" and then the app crashed.
Next, I tried the version 40000000c0 and 40000000c8 with the Terminal.
've tried both variants. Trying 40000000c0 I got an error message, but unfortunately do not know more what it was. Then I looked in the hiddenmenu and saw that the bootloader was unlocked.
Now my problem: Any attempt to boot into the bootloader the phone will hang at the LG logo. I always have to press 10 seconds the power button until it restarts. In the home screen, I get normal, only the bootloader I get the problem mentioned. And I can't also boot into the recovery, even TWRP is installed. Volmue- + Power also dosen't help. It just boot normally into homescreen.
If someone is interested: Before I tried to unlock the bootloader've done a Nandroid backup. All drivers are installed correctly.
Does anyone know how to fix the problem with LG logo?
Information about phone:
Based band version: L6260_MODEM_SIC_02.1233.00
Kernel: 3.1.10
Build Nummber: JZO54K
Version: P88020c-232-10
Hope that was enough information.
Thank you!

Just flash v20a firmware so it would fix recovery and bootloader problems ,then check try to access the bootloader and see if it still gives you an option to unlock it.
Sent from my LG-P880 using xda app-developers app

If you've made a backup.. Surely you have a recovery? you need to do..
Turn on adb and do
adb reboot oem-unlock
You will either get a menu asking whether you want to unlock or it will come up with fastboot... If you get fastboot you have unlocked bootloader I think.. And then you can add the recovery by going to the directory with all your SDK stuff and put the TWRP image there...
Then it's
Fastboot flash recovery [name of recovery].img
Sent from my OptimusX4HD using XDA Premium 4 mobile app

I flashed a new firmware (austria) but it didnt helpt, it still hangs at the lg logo.
Also "adb reboot oem-unlock" didnt work. It just shows me the charging icon and turns off.
Any other ideas?
Thank You.
EDIT: I fixed the problem finally Just flashed the EuroOpen frimware and every thing went fine.
Thanks for the help.

Related

Brick when trying recovery

Hello,
I am totally new in this forum. I got my HTC Vivid one month ago. Today, I wanted to root it. However, it was off and never back, no LED when plugging via USB.
I unlocked BootLoader according to HTC's instruction.
Update HBoot with PH39IMG.zip
Create recovery Nandroid with VIVID_CWM_ROOT_VER2.zip
During the process flashing a Kernel in this forum, I type:
Code:
fastboot flash boot boot.img
fastboot reboot
It rebooted and I stuck in a boot loop (HTC logo just appeared again and again)
I did a Return to stock (http://forum.xda-developers.com/showthread.php?t=1416836). But I only succeeded in first step (fastboot oem lock).
I stuck in bootloader loop. The phone just response in bootloader forever.
I did recovery from Nandroid. It performed restore but not work.
Neither did with the factory reset.
I tried with another PH39IMG.zip (~35 MBs), it worked. I got my phone back.
After that, I wanted to recover since I can't connect to wifi.
Start recovery in bootloader, the phone was just dead. The PC recognized a connection (HSUSB). I download the driver (Qualcomm HS-USB QDLoader 9008
) but no effect.
I think my phone is bricked.
I will appreciate if anyone can help.
cuongcn said:
Hello,
I am totally new in this forum. I got my HTC Vivid one month ago. Today, I wanted to root it. However, it was off and never back, no LED when plugging via USB.
I unlocked BootLoader according to HTC's instruction.
Update HBoot with PH39IMG.zip
Create recovery Nandroid with VIVID_CWM_ROOT_VER2.zip
During the process flashing a Kernel in this forum, I type:
Code:
fastboot flash boot boot.img
fastboot reboot
It rebooted and I stuck in a boot loop (HTC logo just appeared again and again)
I did a Return to stock (http://forum.xda-developers.com/showthread.php?t=1416836). But I only succeeded in first step (fastboot oem lock).
I stuck in bootloader loop. The phone just response in bootloader forever.
I did recovery from Nandroid. It performed restore but not work.
Neither did with the factory reset.
I tried with another PH39IMG.zip (~35 MBs), it worked. I got my phone back.
After that, I wanted to recover since I can't connect to wifi.
Start recovery in bootloader, the phone was just dead. The PC recognized a connection (HSUSB). I download the driver (Qualcomm HS-USB QDLoader 9008
) but no effect.
I think my phone is bricked.
I will appreciate if anyone can help.
Click to expand...
Click to collapse
did u update hboot with an unlocked bootloader...thats no good
are u still can access Hboot?
sometimes, u should flash a kernel with ROM to work on it. if you still running Stock ROM, don;t flash MOD kernel like Holiraider. it will couse boot loop.
if u still able to access HBOTT, no need to worry.
@meatwad0222: I unlocked bootloader and updated hboot. It succeeded in rooting the phone. I got problem when I tried to flash a kernel.
@prahasta: I can't do anything. The phone never turned on again, even if I plugged the charger, the LED was not on. Pressing power button with volume down did not work at all. In general, I can't access to hboot.
Hm... It will be difficult.. hope it wasn't couse by hardware.
Sent from my HTC Raider X710e using xda premium
I had a similar problem..I unlocked bootloader.and flashed a new ROM. I was then stuck in boot loop..it would go all the way to the screen where it says "upgrading android" and would then reboot...the solution I found was to extract the boot image and flash it...then it rebooted normally with new ROM. Hope this helps...
Sent from my HTC PH39100 using xda premium
austin4913 said:
I had a similar problem..I unlocked bootloader.and flashed a new ROM. I was then stuck in boot loop..it would go all the way to the screen where it says "upgrading android" and would then reboot...the solution I found was to extract the boot image and flash it...then it rebooted normally with new ROM. Hope this helps...
Sent from my HTC PH39100 using xda premium
Click to expand...
Click to collapse
if Bootloop, at least u still can access HBoot, but he can't do that.
try to connect it to PC with Full Battery. then check if your PC still detect it. if PC can detect it, try to flash Official RUU.
My laptop does not recognized it. It said that it can't find a driver for that. I searched in xda-forum and I found the driver. Right now, in the device manager of my laptop, it says Qualcomm HS-USB QDLoader 9008. I tried to flash an office RUU but it stopped at <waiting for device>
Thank for your replies.
good to hear your laptop still detect the phone.
u need to pick right RUU for your device.
used Hanson tools, choose to unlock your bootloader again (hope this work). after unlock bootloader, and u can acces HBOOT, choose fastboot mode then instal CMW/WCXs recovery. once done, try to access CWM. if u can acces CWM recovery, there is no worries anymore, u just need to instal correct ROM and Kernel.
My laptop only detects the phone as a Qualcomm chip, not as a phone. When running Hasooon tool, it stops at <waiting for device>.
Sounds like it's in dload mode.
If your phone is in dload mode then I think that is a soft brick...it is fixable, from what I read on another thread, but is more difficult...but not impossible..I had to download HTC drivers for my laptop...the following 2 sites contain the files.
http://forum.xda-developers.com/showthread.php?t=1450105
http://www.theandroidsource.com/viv...65-latest-htc-vivid-sync-driver-download.html
Sent from my HTC PH39100 using xda premium
I talked to HTC customer service for repairing. After everything was set up, I thought that I lost my warranty since I rooted my phone (in HBoot, it said RE-LOCK"). I will give a try with the "wire trick" in the thread "Juopunutbear S-OFF". Hopefully after wire those holes, I can access to the debug mode and "wake up" my phone. Otherwise, I have to spend $5 more to buy those warranty stickers on eBay and have the phone fixed.
I thought that it would be a jtag, but it was not. I did not succeed. I have to send it to HTC for repair.
I think I know the reason caused my problem. I tried to recover why I was on S-ON. Thus, the firmware will "fight" each other and the hardware will not know what it should do. The result is a software-bricked phone.

fastboot: bootloader locked or unlocked?

Hey guys
I noticed that many people are having problems to flash using fastboot. They report that fastboot says the bootloader would be locked, even if it's definitely unlocked.
so my question, who of you is able to flash (kernels for example) using
Code:
adb reboot bootloader
fastboot flash boot boot.img
and who can flash using
Code:
adb reboot oem-unlock
fastboot flash boot boot.img
I've been talking to LG about this problem, but all they said was to change a driver config for ADB. But due to the fact that I'm using Linux, it is impossible that it is a driver problem. I also tried their "solution", but guess what... it didn't work.
first one don't work by me
please use the poll, so that we've got all informations bundled
Hi
I've already voted.
So for me it does not work.Always comes back PERMISSION DENIED.
232.10 3At Austria.
I have rooted and bootloader unlocked.CWM recovery installed.CM 10.1 RC2 installed.
I can flash everything,rom,kernel...
Everything works just Reboot bootloader is not working.
Has an idea? Thanks
I can't really test adb due to idiot computer asking for disk to be inserted. But when I reboot to bootloader it says "now ready" which didn't happen when it was locked. Used the hacked method too, my odm_reserved reads:
0x000000000000000000000000000000000000fdffffffcafffffffdfffefeffed
As @laufersteppenwolf probably knows I am UK 234-000 user, unlocked with the original terminal hacked that blew all our fuses :thumbup:
Sent from my rooted P880
@non4 said:
I can't really test adb due to idiot computer asking for disk to be inserted. But when I reboot to bootloader it says "now ready" which didn't happen when it was locked. Used the hacked method too, my odm_reserved reads:
0x000000000000000000000000000000000000fdffffffcafffffffdfffefeffed
As @laufersteppenwolf probably knows I am UK 234-000 user, unlocked with the original terminal hacked that blew all our fuses :thumbup:
Sent from my rooted P880
Click to expand...
Click to collapse
it's not about the bootloader being locked, it's about the ability to use fastboot for flashing something (kernel for example)
laufersteppenwolf said:
it's not about the bootloader being locked, it's about the ability to use fastboot for flashing something (kernel for example)
Click to expand...
Click to collapse
I know, but does yours say "now ready"? If so then LG really did screw up, idiots
Also if I type "reboot oem-unlock" in terminal I get "welcome to fastboot mode "
Sent from my rooted P880
@non4 said:
I know, but does yours say "now ready"? If so then LG really did screw up, idiots
Also if I type "reboot oem-unlock" I get "welcome to fastboot mode "
Sent from my rooted P880
Click to expand...
Click to collapse
yeah, it says now ready, but fastboot says my bootloader is locked -.-
EDIT: @@non4 already knows LG's answer to this problem, but i think i can tell it y'all:
We are very sorry to say that there is no way to solve the problem you mentioned.
Click to expand...
Click to collapse
nice work LG -.-
laufersteppenwolf said:
yeah, it says now ready, but fastboot says my bootloader is locked -.-
Click to expand...
Click to collapse
You tried typing OEM unlock command? A few people have to do this to get to correct working fastboot mode. In fact I think the guy that got my BL unlocked with his echo odm method had this issue
Sent from my rooted P880
no, i can't ATM...
laufersteppenwolf said:
no, i can't ATM...
Click to expand...
Click to collapse
Reboot oem-unlock works in terminal emulator, that's the only way I can get into "welcome to fastboot" screen. When you can try it, if you can flash stuff through here then we have a solution for you unlucky fellows
Sent from my rooted P880
I'm sorry, but "reboot oem-unlock" does not work.
I just get black screen. :crying:
varadinum said:
I'm sorry, but "reboot oem-unlock" does not work.
I just get black screen. :crying:
Click to expand...
Click to collapse
Weird...
Sent from my rooted P880
Security error for reboot oem-unlock, but manual flash is possible. Normal fastboot says BL is locked, as usual.
Sent from my LG-P880 using Tapatalk 2
maybe you guys can contact LG, too. So they eventually can realize that they've f**ked up, regarding the bootloader...
varadinum said:
Hi
I've already voted.
So for me it does not work.Always comes back PERMISSION DENIED.
232.10 3At Austria.
I have rooted and bootloader unlocked.CWM recovery installed.CM 10.1 RC2 installed.
I can flash everything,rom,kernel...
Everything works just Reboot bootloader is not working.
Has an idea? Thanks
Click to expand...
Click to collapse
maybe my post here helps:
http://forum.xda-developers.com/showthread.php?t=2224020&page=46
adb reboot oem-unlock i got the fastboot welcome screen. i was hoping to see the unlock screen once more because i think something went wrong..
guys, I'm stuck at the CM10.1 boot animation, and after reading numerous posts I found some saying that I need to flash the boot.img through the fastboot. I've managed to go to the Welcome to LG Fastboot Mode though TWRP2.5.0.0 reboot -> bootloader. But when i try fastboot devices my device isn't listed... Any advice on what should I do? Is there any other way to solve the boot issue? I've waited like 15 mins with the phone not getting further than the CM10.1 Logo... :'(
PS: I'm using Minimalistic ADB and Fastboot from here
http://forum.xda-developers.com/showthread.php?p=42407269
both reboot commands "oem-unlock" and "bootloader" are defined in the kernel source code. "oem-unlock" sets an intern hardware flag for booting the unlocked mode and "bootloader" just sets the normal bootloader flag.
wondering why the reboot parameter "recovery" actually only does a normal reboot? (CM has an additional script they call before rebooting to recovery for setting the recovery boot flag)
right, no "recovery" command defined in the kernel source, but its only a few lines of code to add this
------
reboot
bootloader: locked fastboot
oem-unlock: unlocked fastboot
some time ago i messed around with these hardware flags and now oem-unlock doesnt work. it boots instead into recovery lol. no clue why
Gesendet von meinem LG-P880 mit Tapatalk 4 Beta
problem ( Please help quick )
Hi Every One
i have a question
i install new firmware to update hboot
first step to install was relocked bootloader and i did it
after installation i want to unlock my bootloader but my android does not up and freaze on htc one boot animation
how can i unlock my bootloader via fastboot ?? please help me quick

Bootloader won't start

After a long search, I couldn't find anything related to this issue, that's why I've posted this here.
So I tried to root an LG 4X HD, I rooted it immediately without unlocking BL, now everytime I boot into bootloader, I get this:
[LGE_SECURITY] ERROR: boot image signature
Critical failure: unable to start kernel
Unrecoverable bootloader error (0x0000002)
Android (ICS) boots just fine, has root access... but can't access recovery
I know I did something wrong here, little help?
Sent from my LG G2 using Tapatalk... Awesome
Unlock the boot loader
don't forget to hit thanks!
abhi08638 said:
Unlock the boot loader
don't forget to hit thanks!
Click to expand...
Click to collapse
Tried that, won't get into OEM BL unlock mode... it's just odd.
Sent from my LG G2 using Tapatalk... Awesome
hanisod said:
Tried that, won't get into OEM BL unlock mode... it's just odd.
Sent from my LG G2 using Tapatalk... Awesome
Click to expand...
Click to collapse
On ICS you can't unlock bootloader, try upgrading to JB.
Press thanks if it helps
hanisod said:
After a long search, I couldn't find anything related to this issue, that's why I've posted this here.
So I tried to root an LG 4X HD, I rooted it immediately without unlocking BL, now everytime I boot into bootloader, I get this:
[LGE_SECURITY] ERROR: boot image signature
Critical failure: unable to start kernel
Unrecoverable bootloader error (0x0000002)
Android (ICS) boots just fine, has root access... but can't access recovery
I know I did something wrong here, little help?
Sent from my LG G2 using Tapatalk... Awesome
Click to expand...
Click to collapse
My problem is same as yours or nearly the same.
I unlocked bootloader on V20a with "adb reboot oem-unlock" and installed CWM + CM11. Everything was working fine, but GPS. From time to time loses signal, takes more minutes to get lock, etc...
I read somewhere on this forum that there is a problem with the V20x basebands and the solution is to roll back to V10x. So I flashed back to V10H with .dz file. When I type "adb reboot bootloader", "adb reboot-bootloader" or "adb reboot oem-unlock" the phone just restarts. (At this point I can boot into LG's recovery.) Rooted the system and flashed CWM recovery from shell. When I want to boot in to new recovery then appears this message. (I can boot into system.)
Again if I flash back the V20a, I can boot into bootloader and can install custom recovery (without re-unlocking).
I would like to know, how could I manage to work V10x+CWM+CM11 together
jeBACH said:
My problem is same as yours or nearly the same.
I unlocked bootloader on V20a with "adb reboot oem-unlock" and installed CWM + CM11. Everything was working fine, but GPS. From time to time loses signal, takes more minutes to get lock, etc...
I read somewhere on this forum that there is a problem with the V20x basebands and the solution is to roll back to V10x. So I flashed back to V10H with .dz file. When I type "adb reboot bootloader", "adb reboot-bootloader" or "adb reboot oem-unlock" the phone just restarts. (At this point I can boot into LG's recovery.) Rooted the system and flashed CWM recovery from shell. When I want to boot in to new recovery then appears this message. (I can boot into system.)
Again if I flash back the V20a, I can boot into bootloader and can install custom recovery (without re-unlocking).
I would like to know, how could I manage to work V10x+CWM+CM11 together
Click to expand...
Click to collapse
you need to mod 20x kdz with 10x baseband, and flash that. there's a tutorial somewhere around the forum, search and you'll find it.
The tutorial that Flying_Bear is talking about is:
[BASEBANDS][TUTORIAL] Freedom! Choose your baseband.

[Q] ***TAMPERED*** ***UNLOCKED*** Phone stuck in bootloader

Hi,
Today i attempted to unlock my phones bootloader and flash TWRP (twrp-2.8.1.0-20142812-memul). I unlocked it fairly easily using the htc.dev website but encountered an issue when trying to flash the Recovery. The phone is stuck in the bootloader with the message ***TAMPERED*** ***UNLOCKED*** showing at the top. I cannot get off this and every attempt to get into the phone, such as by clicking on Reboot or holding the POW+VOL UP+VOL DOWN buttons, has failed, simply dumping me back on the bootloader homescreen. Does anybody know how to solve this issue?
Kind regards
James
Try re-flashing recovery from fastboot on your pc, I would even try redownloading the recovery just to be sure you didn't get a corrupted copy previously, also clear cache after flashing recovery.
The tampered message is normal so just ignore that.
You can even try rebooting boot loader and or recovery using fastboot commands, just search fastboot commands on Google and you'll find a list of relevant commands.
Jameswebb97 said:
Hi,
Today i attempted to unlock my phones bootloader and flash TWRP (twrp-2.8.1.0-20142812-memul). ...
Kind regards
James
Click to expand...
Click to collapse
there's a few problems with TWRP i notice in other phones. one of them was stuck in bootloader.
my solution was remove usb cable before rebooting.
got same issue...
Jameswebb97 said:
Hi,
Today i attempted to unlock my phones bootloader and flash TWRP (twrp-2.8.1.0-20142812-memul). I unlocked it fairly easily using the htc.dev website but encountered an issue when trying to flash the Recovery. The phone is stuck in the bootloader with the message ***TAMPERED*** ***UNLOCKED*** showing at the top. I cannot get off this and every attempt to get into the phone, such as by clicking on Reboot or holding the POW+VOL UP+VOL DOWN buttons, has failed, simply dumping me back on the bootloader homescreen. Does anybody know how to solve this issue?
Kind regards
James
Click to expand...
Click to collapse
I had that issue according to my version of TWRP. Try it with 2.8.5.0. After i re-flashed it with that, all worked fine. Give me feedback if you could solve it.
agh well after ages of trying different methods nothing worked. Even took it to my local phone shop who do software tweaks and recovery, the guy told me the entire Android OS had been removed...? Gave up and bought a new phone, thank you guys for trying anyway <3

How to Re-Lock Bootloader?

I need to lock my bootloader to do an exchange at T-Mobile. I have 20R stock flashed, but it still says custom bootloader upon boot, how do I relock it safely?
I read that "fastboot oem lock" will work, but will brick it if I don't do it perfectly. Any advice on what to do?
TechGuruGJ said:
I need to lock my bootloader to do an exchange at T-Mobile. I have 20R stock flashed, but it still says custom bootloader upon boot, how do I relock it safely?
I read that "fastboot oem lock" will work, but will brick it if I don't do it perfectly. Any advice on what to do?
Click to expand...
Click to collapse
ive done it .. it works. it will build dalvik once it reboots.
I was able to Lock the bootloader.
1. I connected the phone to my PC
2. Powered on the Phone (it took a few tried of pulling the battery and powering on)
3. Check the box for OEM Unlock in Dev. Option
4. Use Minimal ADB and Fastboot and type in
Quote:
adb devicecs
- you should see the phone listed as one of the devices in the command line window
Quote:
adb reboot bootloader
- phone should reboot and you shouold see 3 lines of text on top
Quote:
fastboot oem lock
- nothing will happen on the phone, but on in the commandline it should say that it is done
Quote:
fastboot reboot
Phone reboots and the boot screen does not show the unlocked bootloader message anymore
I'm terribly sorry if bumping is not ok.
Thought it wasn't worth making a new thread, since my post is about the one above.
Has anybody actually tried these steps above? (Since every other thread mentioning this says it's a one-way only thing..)
Does locking the bootloader means also loosing the custom recovery? (I'd expect that, but asking to be sure)
Does it return the phone to it's original state? (ie. before one unlocked the bootloader, or there are some differences?)
Does it also means I would be able to get official OTA updates and so on? (since with a custom recovery, that's not possible)
Thanks in advance.
Yes, it does work. I did it, worked perfectly. Yes it does return your device to it's original state. Just make sure the stock ROM is flashed and all should be well. I didn't try, but I see no reason why it wouldn't let you get OTA updates from T-Mobile. Let me know if you need help.
Nadeox1 said:
I'm terribly sorry if bumping is not ok.
Thought it wasn't worth making a new thread, since my post is about the one above.
Has anybody actually tried these steps above? (Since every other thread mentioning this says it's a one-way only thing..)
Does locking the bootloader means also loosing the custom recovery? (I'd expect that, but asking to be sure)
Does it return the phone to it's original state? (ie. before one unlocked the bootloader, or there are some differences?)
Does it also means I would be able to get official OTA updates and so on? (since with a custom recovery, that's not possible)
Thanks in advance.
Click to expand...
Click to collapse
ive said ive done it. on the above instructions you dont beleive.??
i think you loose the twrp phone doesnt show unlocked bootloader message did not check recovery but it must revert t stock one.. not sure about OTA since am not in tmobile network.
you dont need OTA. you can always download KDZ and flash it with LGUP.
and stay uptodate.
raptorddd said:
ive said ive done it. on the above instructions you dont beleive.??
i think you loose the twrp phone doesnt show unlocked bootloader message did not check recovery but it must revert t stock one.. not sure about OTA since am not in tmobile network.
you dont need OTA. you can always download KDZ and flash it with LGUP.
and stay uptodate.
Click to expand...
Click to collapse
Thanks both for replying.
And no @raptorddd , I did not mean that.
Your post is the only mentioning that locking the bootloader is possible, while all the other similar threads have ony people saying otherwise / it's not possible. I guess a slightly doubt is legit to have, don't take it wrongly
raptorddd said:
ive done it .. it works. it will build dalvik once it reboots.
I was able to Lock the bootloader.
1. I connected the phone to my PC
2. Powered on the Phone (it took a few tried of pulling the battery and powering on)
3. Check the box for OEM Unlock in Dev. Option
4. Use Minimal ADB and Fastboot and type in
Quote:
adb devicecs
- you should see the phone listed as one of the devices in the command line window
Quote:
adb reboot bootloader
- phone should reboot and you shouold see 3 lines of text on top
Quote:
fastboot oem lock
- nothing will happen on the phone, but on in the commandline it should say that it is done
Quote:
fastboot reboot
Phone reboots and the boot screen does not show the unlocked bootloader message anymore
Click to expand...
Click to collapse
I have follow this instructions and now it giving me and error. Any fix??
WARMANH811 said:
I have follow this instructions and now it giving me and error. Any fix??
Click to expand...
Click to collapse
What error?
TechGuruGJ said:
What error?
Click to expand...
Click to collapse
Secure booting Error!
Error code: 1003
MODIFIED ! !
WARMANH811 said:
Secure booting Error!
Error code: 1003
MODIFIED ! !
Click to expand...
Click to collapse
are you sure you have h811.? i did not get that error ive tried this twice..
i remeber getting an security boot error on LG G2 i fix by flashing firmware .. so maybe KDZ could help..
if not am not sure then search for that error and find out how to fix.
raptorddd said:
ive done it .. it works. it will build dalvik once it reboots.
I was able to Lock the bootloader.
1. I connected the phone to my PC
2. Powered on the Phone (it took a few tried of pulling the battery and powering on)
3. Check the box for OEM Unlock in Dev. Option
4. Use Minimal ADB and Fastboot and type in
Quote:
adb devicecs
- you should see the phone listed as one of the devices in the command line window
Quote:
adb reboot bootloader
- phone should reboot and you shouold see 3 lines of text on top
Quote:
fastboot oem lock
- nothing will happen on the phone, but on in the commandline it should say that it is done
Quote:
fastboot reboot
Phone reboots and the boot screen does not show the unlocked bootloader message anymore
Click to expand...
Click to collapse
My H811 T-mobile phone needs service. It has original 20v software version. It is unlocked with TWRP and rooted. Can I use this method? Do I first have to downgrade software to some other version? Will this method also take out TWRP and root or do I still have to take them out before doing this? How? Please help.
joecandle said:
My H811 T-mobile phone needs service. It has original 20v software version. It is unlocked with TWRP and rooted. Can I use this method? Do I first have to downgrade software to some other version? Will this method also take out TWRP and root or do I still have to take them out before doing this? How? Please help.
Click to expand...
Click to collapse
no need to downgrade. to remove root and any trace if phone works. is to use KDZ then once it boots into system do the lock procedure. so it locks and the small white letter are removed. this way its like stock rom and recovery and the above commmands will make bootloader locked. and sent to repair. if bootloops try the freezing method.
Used on an LG Aristo that has Cyanogen and it worked
raptorddd said:
ive said ive done it. on the above instructions you dont beleive.??
i think you loose the twrp phone doesnt show unlocked bootloader message did not check recovery but it must revert t stock one.. not sure about OTA since am not in tmobile network.
you dont need OTA. you can always download KDZ and flash it with LGUP.
and stay uptodate.
Click to expand...
Click to collapse
This was the only one i found that didnt brick my phone and trust me ive bricked and unbricked this phone many times
When you use the fastboot command to lock back your bootloader, the phone doesn't revert automatically to the stock recovery and actually that is partly the reason why it bricks and other main reason is that changes made to bootloader to obtain root brick the phone. before you relock bootloader, if you have SuperSU (in-app menu option) or Magisk (uninstall zip file), use their respective methods to unroot the phone, then use twrp to flash .image file of stock recovery to recovery partition then use the fastboot command to lock the bootloader. Even then it may or may not work because if whatever method the phone uses to check the integrity of bootloader and/or recovery, such as md5, if it doesn't match, the phone will still brick. Since all your data on phone will be erased regardless as soon as you lock the bootloader, i personally just fastboot lock the bootloader, remove battery to power down, use the volume up and plug usb cable in from pc to put phone in download mode and just use LGUP (uppercut) if have kdz file already, which i do, i just let LG Bridge download the file, find it in programs folder and copy it to another location before LG Bridge deletes it --OR-- just use error recovery option in Software Update tab in LG Bridge as both LGUP and LG Bridge will detect the phone in download mode even if it is bricked.
By the way, I have used both methods above dozens of times without any issues, someone above who mentioned phone boot-looping because of locking the bootloader, it is boot-looping not because of hardware flaw which was widespread in LG G3 but a software issue (phone boots up, doesn't find the software configuration it is looking for and just restarts) and they are not the same issues, no need to freeze the phone, won't help.
the method works, but no OTA from T-Mobile. "verification problem".
When I try to "adb reboot bootloader" I get "security error".
If I try reboot recovery, TWRP is definitely not there.
Just want to update from20Q to 20X.
Any help would be appreciated.
metropical said:
the method works, but no OTA from T-Mobile. "verification problem".
When I try to "adb reboot bootloader" I get "security error".
If I try reboot recovery, TWRP is definitely not there.
Just want to update from20Q to 20X.
Any help would be appreciated.
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The above points to you not giving permission possibly because either you missed the permission pop-up or selected option that didn't allow permission.
Can anyone help me?
When i unlock bootloader on my lg velvet 4g the fingerprint stop working so i want to relock. But when i put this on cmd "adb reboot bootloader" it only restarts my phone. Doesnt shows me the bootloader menu it only restarts normaly
Lukasz23 said:
Can anyone help me?
When i unlock bootloader on my lg velvet 4g the fingerprint stop working so i want to relock. But when i put this on cmd "adb reboot bootloader" it only restarts my phone. Doesnt shows me the bootloader menu it only restarts normaly
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managed to solve?

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