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NEXUS S EUR Bricked OEM UNLOCK ERASE FAIL

Hey guys, i've a big problem.
Yesterday, suddently my nexus s didn't boot. It was stucked on Google logo.
It's rooted and it has the cm7 rom.
I tryed to reflash with cw recovery but i have an issue.
I cannot copy nothing on the sdcard partition.
I mount it with recovery and correctly copy the img from my pc. After i sync and dismount but if i remount the sdcard i cannot see the file that i've copied before.
It seems strange because if i try to format sdcard from recovery it says "done" but the data still remain.
After that i tried to lock and reunlock my phone but it fail.
I launch the command fastboot oem unlock, correctly the two-choices window appear, i select yes but on my pc i see (erase fail) and bootload remain unlocked.
Please give me some advice to resurrect my phone.
Thanks for the support, and sorry for my bad english.
Emiliano

fastboot oem unlock wont lock it, use fastboot oem lock.

i need to unlock it. i've locked now i need to unlock.
But the procedure
fastboot oem unlock
fail with erase fail errore.

I had almost the exact same problem yesterday. Tried literally everything and nothing worked. In fact it kept getting a little worse with every battery pull/reboot.
I purposely re locked the boot loader, right before I went to Sprint and paid $38 for a working replacement.
Probably be a good long while before I root another phone.
Sent from my Nexus S 4G using Tapatalk

After 4.0.4 OTA update device is bricked.
I have experienced the same issue you are discussing here.
A couple of days ago I received an OTA update to android 4.0.4 for my Nexus S device, vodafone UK. My phone is NOT rooted or OEM unlocked. The update downloaded but fails to install on reboot. The phone just returns to the original state, with the update waiting to install.
Any app or software will not work on the device, force closes error. If I attempt to restore to any factory settings or wipe / format the phone by any method you can come up with in a google search!, once the device reboots this change is ignored. If I copy any file on the Mass storage via usb, after the phone reboots the file is gone.
I've attempted to unlock the oem to flash the device in an attempt to resolve this, however when using ./fastboot oem unlock I get the following error:
... FAILED (remote: Erase Fail)
It seems the device has been screwed some how after receiving this update. It can only be a hardware error now....
Who is now responsible to fix this? i have had this Nexus S over 1 year now, can I take to Samsung or Vodafone for these guys to get repaired?

Sounds like hardware issue. Have you tried formatting the sdcard in windows or running chkdsk /F.

I Have Same Problem how can i fix it?
LeeVidor said:
I have experienced the same issue you are discussing here.
A couple of days ago I received an OTA update to android 4.0.4 for my Nexus S device, vodafone UK. My phone is NOT rooted or OEM unlocked. The update downloaded but fails to install on reboot. The phone just returns to the original state, with the update waiting to install.
Any app or software will not work on the device, force closes error. If I attempt to restore to any factory settings or wipe / format the phone by any method you can come up with in a google search!, once the device reboots this change is ignored. If I copy any file on the Mass storage via usb, after the phone reboots the file is gone.
I've attempted to unlock the oem to flash the device in an attempt to resolve this, however when using ./fastboot oem unlock I get the following error:
... FAILED (remote: Erase Fail)
It seems the device has been screwed some how after receiving this update. It can only be a hardware error now....
Who is now responsible to fix this? i have had this Nexus S over 1 year now, can I take to Samsung or Vodafone for these guys to get repaired?
Click to expand...
Click to collapse
please anyone can help me how can i fix my mobile ...

You can't. It's a hardware common issue without any solution. Better sent it to repair. My two cents
Sent from my
( •_•)
( •_•)>⌐■-■
Nexus S
(⌐■_■)
YYYYYYYEEEEEAAAAAAAAAAHHHHHHHHHHHH

sammme problem har you fix it?
benazhack said:
i need to unlock it. i've locked now i need to unlock.
But the procedure
fastboot oem unlock
fail with erase fail errore.
Click to expand...
Click to collapse
please help me if u get the solution plz

zaherrrr said:
please help me if u get the solution plz
Click to expand...
Click to collapse
Already been posted, you can't, warranty repair or you need to replace the main board(guessing £100-200?)
Sent from my ice cream powered Nexus S

DarkhShadow said:
Already been posted, you can't, warranty repair or you need to replace the main board(guessing £100-200?)
Sent from my ice cream powered Nexus S
Click to expand...
Click to collapse
Just figured something out, i had the same issues as described above, could only boot the phone with a hair dryer
The new update Jelly Bean 4.1.1 is more forgiving when it comes to booting (probably voltages of the internal SD!! I'm still testing, but as far as i can see now, the phone boots normally again now (no more stuck on the google logo)
My problems:
- Not able to unlock bootloader (erase failed).
- Not possible to boot normally due to faulty internal SD card (only able to boot with the 'hairdryer' trick).
What did i do:
- Just tried the same as the trick on booting: use the hairdryer when fastbooting!!!
- Have everything ready; cmd, fastboot files, drivers etc, phone connected to computer with USB.
- Try to boot it first after heating the phone with the hairdryer (get past the google logo) and then immediately remove the battery.
- Then boot into fastboot mode (power and vol. up).
- Immediately execute the 'fastboot oem unlock' command.
Voila, that did the trick for me. Status OKAY and my bootloader was unlocked.
Then ROOT and update the phone to 4.1.1 with the following instructions:
(not able to unclude link, see webtrickz dot com/guide-to-manually-update-nexus-s-i9020ti9023-to-android-4-1-1-jelly-bean)
That did the trick for me!
NO MORE HAIRDRYER FOR ME!!

OEM unlock FAILED (remote: Erase Fail)
Hi
I'm replying to this message to share my experience about the same issu i had.
I bought a broken nexus s on google, auction described the phone as messed up during some software update. When cell got here:
- Bootloader was loading and locked
- Bootloader was reporting no boot image and no recovery
- Recovery was flashed with cwm 6.0.1.0
When trying to oem unlock, I was getting "FAILED (remote: Erase Fail)" no matter what I try. My config was good i've unlocked many nexus s with the same setup.
In recovery I was not able to mount sdcard, system, boot, nothing was working as it should.
After many frustrating hours, i saw this post.. What a stupid idea.. But I have nothing to loose at this point.
I don't have a hair dryer but I do have an oven. I figured the idea was to get the phone really hot..
Set the oven to 170, convection on and cooked the phone without the battery and cover for about 5 minutes until it was really hot but not melting.
Did the oem unlock and guess what.. It worked on first try.
After that I was able to update bootloader, radio, recovery and installed latest cm10. I've wipped the phone a couple of time, tried everything I could think of to test if something is not working, but everything does..
No hair dryer?
Just cook you phone at 170 for 5 minutes.
Worked for me.. go figure..
hetile
TimeClypse said:
Just figured something out, i had the same issues as described above, could only boot the phone with a hair dryer
The new update Jelly Bean 4.1.1 is more forgiving when it comes to booting (probably voltages of the internal SD!! I'm still testing, but as far as i can see now, the phone boots normally again now (no more stuck on the google logo)
My problems:
- Not able to unlock bootloader (erase failed).
- Not possible to boot normally due to faulty internal SD card (only able to boot with the 'hairdryer' trick).
What did i do:
- Just tried the same as the trick on booting: use the hairdryer when fastbooting!!!
- Have everything ready; cmd, fastboot files, drivers etc, phone connected to computer with USB.
- Try to boot it first after heating the phone with the hairdryer (get past the google logo) and then immediately remove the battery.
- Then boot into fastboot mode (power and vol. up).
- Immediately execute the 'fastboot oem unlock' command.
Voila, that did the trick for me. Status OKAY and my bootloader was unlocked.
Then ROOT and update the phone to 4.1.1 with the following instructions:
(not able to unclude link, see webtrickz dot com/guide-to-manually-update-nexus-s-i9020ti9023-to-android-4-1-1-jelly-bean)
That did the trick for me!
NO MORE HAIRDRYER FOR ME!!
Click to expand...
Click to collapse

hetile said:
Hi
I'm replying to this message to share my experience about the same issu i had.
I bought a broken nexus s on google, auction described the phone as messed up during some software update. When cell got here:
- Bootloader was loading and locked
- Bootloader was reporting no boot image and no recovery
- Recovery was flashed with cwm 6.0.1.0
When trying to oem unlock, I was getting "FAILED (remote: Erase Fail)" no matter what I try. My config was good i've unlocked many nexus s with the same setup.
In recovery I was not able to mount sdcard, system, boot, nothing was working as it should.
After many frustrating hours, i saw this post.. What a stupid idea.. But I have nothing to loose at this point.
I don't have a hair dryer but I do have an oven. I figured the idea was to get the phone really hot..
Set the oven to 170, convection on and cooked the phone without the battery and cover for about 5 minutes until it was really hot but not melting.
Did the oem unlock and guess what.. It worked on first try.
After that I was able to update bootloader, radio, recovery and installed latest cm10. I've wipped the phone a couple of time, tried everything I could think of to test if something is not working, but everything does..
No hair dryer?
Just cook you phone at 170 for 5 minutes.
Worked for me.. go figure..
hetile
Click to expand...
Click to collapse
I'm speechless..hair dryer works for me too!!! THANK YOU GUYS!

fastboot oem unlock goes to lock after reboot

I have a Nexus 5 that I purchased from Ebay, and I'm trying to flash stock krt16m to get the device working.
Here are some things that I've noticed:
When I fastboot oem unlock, I will see the lock state change to unlock, but then when I execute fastboot reboot-bootloader, the lock state after reboot will show locked.
This presents a problem when trying to run the script flash-all.sh because upon reboot of the boot-loader I'm unable to flash other images. So, I modified the script to do the following:
fastboot flash bootloader bootloader-hammerhead-HHZ11d.img
fastboot reboot-bootloader
fastboot oem unlock
sleep 10
fastboot flash radio radio-hammerhead-M8974A-1.0.25.0.17.img
fastboot reboot-bootloader
fastboot oem unlock
sleep 10
fastboot -w update image-hammerhead-krt16m.zip​
so that I could change the lock state to unlocked after every reboot before flashing the next image.
This succeeds, but when the Nexus 5 boots, it gets stuck in an 'X' boot loop. Sometimes I see messages like Unfortunately google.process.gapps failed, or similar. I'll also get into X boot loops where I don't get error messages, but I do get messages like, "Starting apps" and similar.
I tried factory reset/wipe in recovery mode, to no avail. I get error messages like, "failed to mount cache".
I tried flashing the stock cache, then formatting it, to no avail.
I also tried to sideload the stock images with adb when in recovery mode. Also to no avail.
The Ebay listing didn't give much information, but it did mention that this was a T-Mobile Nexus 5.
Help me! What else can I do?

Sounds like a nand failure. The boot loader staying locked is a key indicator of that. There's not really much more you can do.

theesotericone said:
Sounds like a nand failure. The boot loader staying locked is a key indicator of that. There's not really much more you can do.
Click to expand...
Click to collapse
Just to be clear, we're talking about the part: Sandisk SDIN8DE4 16 GB NAND flash?
Is there anyway that I can prove it's bad, besides the bootloader not staying in an unlocked state?

seanmeir said:
Just to be clear, we're talking about the part: Sandisk SDIN8DE4 16 GB NAND flash?
Is there anyway that I can prove it's bad, besides the bootloader not staying in an unlocked state?
Click to expand...
Click to collapse
The bootloader and the fact that you can't format anything are key signs. It's happened quite a few times on the N5 and I'm not aware of anyone who was able to fix it. Keep in mind I don't have the device in my hand but the symptoms you are describing are those of a bad nand.

I'd also vote for a corrupted NAND (As far as I remember, in the best situation the only way to fix a bad NAND is to power cycle it again.. and good luck doing that.. in the worst its just dead.). You bought a broken phone .
Also you don't need much more: If after rebooting the NAND is in the previous state, whatever you do, the NAND is broken.

Yes, your eMMC is definitely dead/damaged. It has happened to a few people, and it was the exact same every time. RMA or send in for repairs.
No one is going to "fix" the eMMC itself, not even LG, as it isn't worth the effort nor cost to do so. Any repair job will simply be a motherboard swap.

nexus 5 is dead?

hi - i have in my nexus 5 only the google logo and the unlocked key is on the screen;
when i get to fast boot it does see the device.
when ienter " fastboot oem device-info
igot device tampered true
device unlock true
off mode charge - true
when i try to write twrp recovery it says sending recovery okay and writing recovery okay.
but ucant enter to the recovery of twrp.
when i try to flash an image it says:
writing bootloader
failed (remoteflash write failure)
rebooting into bootloader okay
writing radio - failed remoteflash write failure
target reported max size of 1073741824bytes
is there any way to save my phone?
i can enter adb its says on the phone "now send the package you want to apply to the device with "adb sideload filename"..
how do i can send an image?
thank u

re
i try to flash with the lg flash rool - i did everything ok and it stuck in 6% and says"user data erase fail" what can i do?

You're using the batch commands included with the stock ROM to re-flash?

Hi my Nexus 5 also suddenly die too. And I have the same exact problem that you have when trying to flash it. I looked for hours on the internet tried formatting, erasing and many other alternatives and nothing. There are some people experiencing this same problem like us. For no reason the memory is getting corrupt or died. I get mant errors on the cache when I boot to regular recovery. The only recovery that I have manage to boot to (except for the original one) is Clockworkmod using fastboot boot "therecoveryname.img". With clockworkmod I have adb working but still can get the phone to boot or accept factory images. I can't lock the bootloader either.
I think this error was cause by the software. There was a very similar problem that never got fixed for the nexus 7 when lollipop came out.

Do you need to lock the bootloader? Once locked, you cannot flash anything via fastboot commands, not even a stock ROM.

No I don't need to. I tried just to see if the phone will relock itself. I read somewhere in the internet that if you can't relock/unlock the device the nand if fried.
If you look for these errors there are people with LG G2 and LG G3 that are having something similar happen. I think LG hardware is partly behind the problem. I call Google and told them about it and the put me through LG which want me to send the phone for repairs but not free. My guess is that it will be way to expensive to repair and that is not worthy.
Hopefully someone with real repair skill can give us light if this is something fixable by software.
audit13 said:
Do you need to lock the bootloader? Once locked, you cannot flash anything via fastboot commands, not even a stock ROM.
Click to expand...
Click to collapse

I had two different Nexus 5 phones that were stuck in a bootloop with the spinning coloured KK animation.
Every time I unlocked the bootloader, the bootloader would always re-lock itself when rebooting. Even when I managed to unlock the bootloader, I could not re-flash a stock ROM because the bootloader kept relocking itself.
Whenever I unlocked the bootloader, the phone would only take 2 ot 3 seconds to wipe the phone which is too fast.
In the end, I purchased a nexus 5 with a smashed screen to use its motherboard in my defective N5.
I have never come across a post where someone was able to solve the problem unless they had LG replace the motherboard with a new imei.

Retard in need of Help. Weird problem with recovery of my OPO

Alright have read the first 30 pages of comments on http://forum.xda-developers.com/oneplus-one/development/mod-reset-unlock-tamper-bit-t2820912 and I starting to feel like I'm dumber then a brick.
Okay here is my problem: Just bought a used OPO with the classic boot logo loop error. I have tried to just simply Factory reset it (both Full and wipe cache) and it gives me E: failed to mount /cache (invalid argument) error. Then I googled it and most of the results said that I need to simply reinstall the software with adb. Okay got adb up and running and installed my phones drivers and booted into fastboot.
Then when I try to install it gave me "device not unlocked" error... Fine googled it tried "fastboot oem unlock" and it was still not unlocked.
Googled that and read the posts about tampered bits and after running the "fastboot oem device-info" It gives me "Device tampering: true" "Device unlocked: false" so damn.
Then I read the posts and tried to sideload OnePlusOne-BootUnlocker.zip (used the "apply update" in cyanogen recovery to get the ADB sideload) but it comes up with E: failed to mount /cache (invalid argument) and fails all the other things.
Have tried "fastboot boot recovery recovery.img" but that have the have a unlocked bootloader.
I'm abit lost ATM because I discovered that wile I can get fastboot and Sideload (from update) to show my device the normal adb can't see it when just being in the menu.
So if one of you could point me in the right way or if you got time guide me then I would be greatfull.
Regards Magnus/Mjallo
PS. Please don't burn me for asking

Can post pictures of the screen if it is needed

@Mjallo google "Bacon Toolkit."
Does literally all the things you are trying to do in a matter of a few clicks. Walks you through everything step by step.

h11wiscan said:
@Mjallo google "Bacon Toolkit."
Does literally all the things you are trying to do in a matter of a few clicks. Walks you through everything step by step.
Click to expand...
Click to collapse
Okay have played around with the program abit more and all it does is that same as me doing it in CMD.
I still have the problem with Device tampering and device unlock state. Where is the tools for fixing that?
Have tried to fix the cache but it still make the invalid argument.

might could fastboot flash official images to get the phone back to normal. you dont have to have bootloader unlocked to flash official boot images. you can go here https://cyngn.com/support and download the cm-13.1-ZNH2KAS254-bacon-signed-fastboot-d194f46bee.zip (scroll down to opo section) and/or go to http://forum.xda-developers.com/oneplus-one/general/guide-return-opo-to-100-stock-t2826541 and get the download and follow directions in that post to flash phone

Mjallo said:
Okay have played around with the program abit more and all it does is that same as me doing it in CMD.
I still have the problem with Device tampering and device unlock state. Where is the tools for fixing that?
Have tried to fix the cache but it still make the invalid argument.
Click to expand...
Click to collapse
Yeah idk then. Need more screenshots or info to help. Could be a million things.
-Are you using OEM USB cable?
-Did you install ALL drivers properly?
-Have you rebooted since installing ALL drivers?
-Have you tried using bacon toolkit on another computer? Sometimes simply switching computers can help.
-Did you try resetting phone to factory state using ABD/Bacon Toolkit?
-In Bacon Toolkit did you select the proper firmware and software version before attempting to use the program?
A few questions to ask yourself before we go further.

kenboyles72 said:
might could fastboot flash official images to get the phone back to normal. you dont have to have bootloader unlocked to flash official boot images. you can go here https://cyngn.com/support and download the cm-13.1-ZNH2KAS254-bacon-signed-fastboot-d194f46bee.zip (scroll down to opo section) and/or go to http://forum.xda-developers.com/oneplus-one/general/guide-return-opo-to-100-stock-t2826541 and get the download and follow directions in that post to flash phone
Click to expand...
Click to collapse
Have tried with both Normal Cyanogen and CyanogenMOD (that is what the bootlogo says on this phone) and both of them give the Device not unlocked error both on screen and in CMD

h11wiscan said:
Yeah idk then. Need more screenshots or info to help. Could be a million things.
-Are you using OEM USB cable?
-Did you install ALL drivers properly?
-Have you rebooted since installing ALL drivers?
-Have you tried using bacon toolkit on another computer? Sometimes simply switching computers can help.
-Did you try resetting phone to factory state using ABD/Bacon Toolkit?
-In Bacon Toolkit did you select the proper firmware and software version before attempting to use the program?
A few questions to ask yourself before we go further.
Click to expand...
Click to collapse
Okay I'm using the OEM cable (have tried both the one I got with this phone and the one I got with my Orginal OPO)
Have gone through the steps checking my drivers and they should be working and A OKAY, reboot and all.
Don't have access to another pc ATM but will look after the option.
Have tried all the option in Bacon toolkit to reset the phone to factory setting and non is working, tried to then use the recovery option to maybe get it to work that way but no dice. Have also tried sideloading both with Toolkit and with CMD and no luck their either. Took a picture of the screen when the sideload tries to work.
http://imgur.com/6L74N6J
The Firmware question is up in the air because I have never got it booted so I have no clue what firmware it has only hint that the boot screen is Cyanogen MOD READY and not just Cyanogen like on my other OPO
Hope it helps finding the problem

I super hard bricked my phone a while back, even lost a partition. I was finally able to get it back by flashing colorOS. took a few tries to get the program to recognize my phone, but finally got it flashed. The phone never booted all the way up with colorOs, but it fixed what needed fixed and I was then able to fastboot flash CM13, unlock bootloader and go from there. don't have that thread bookmarked, but it's here in the forums.
Edit: found thread http://forum.xda-developers.com/oneplus-one/general/guide-unbrick-oneplus-one-t3013732

kenboyles72 said:
I super hard bricked my phone a while back, even lost a partition. I was finally able to get it back by flashing colorOS. took a few tries to get the program to recognize my phone, but finally got it flashed. The phone never booted all the way up with colorOs, but it fixed what needed fixed and I was then able to fastboot flash CM13, unlock bootloader and go from there. don't have that thread bookmarked, but it's here in the forums.
Edit: found thread http://forum.xda-developers.com/oneplus-one/general/guide-unbrick-oneplus-one-t3013732
Click to expand...
Click to collapse
It sadly did not fix the problem it gives this problem and just stops working (need to close it in taskmanger) http://imgur.com/w1zOQFU.
Well the quest goes on

Mjallo said:
It sadly did not fix the problem it gives this problem and just stops working (need to close it in taskmanger) http://imgur.com/w1zOQFU.
Well the quest goes on
Click to expand...
Click to collapse
when you run the program, one of the columns should have a few random characters and "com" in it. if you dont see com in any of the columns, then the program is not seeing you phone. if you do see com, the click on that row and press start and it will show files being written in green showing progress. if phone is not being seen, follow that guide to the letter, specially if this is on a win7/8 machine. i will get my lappy out in a bit and give a few screenies on what it should look like, i wont actually flash my phone though.

kenboyles72 said:
when you run the program, one of the columns should have a few random characters and "com" in it. if you dont see com in any of the columns, then the program is not seeing you phone. if you do see com, the click on that row and press start and it will show files being written in green showing progress. if phone is not being seen, follow that guide to the letter, specially if this is on a win7/8 machine. i will get my lappy out in a bit and give a few screenies on what it should look like, i wont actually flash my phone though.
Click to expand...
Click to collapse
It sees it (you can see it in COM5 in the picture) and when the progress bar shows it just make a little green tip then just stops showing

are you running the program as administrator? right click on exe and select run as administrator? other than that, don't see why it's not flashing and I'm out of ideas, sorry.

How to flash a corrupted Google Nexus?

Dear friends,
I have LG Google Nexus 5 (Hammerhead D821(H) 32GB) model. Some days ago I tried to install Ubuntu Touch OS through UBports Software in my nexus 5 phone. But I forgot to enable USB Debugging first. So when I started the flash process and try to unlock bootloader, one time it show lock state unlocked. But In reality it was not unlocked. Because of this reason Ubuntu Touch OS installation is not completed and it corrupted my phone. Now I am unable to boot in android also. I also tried to re-flash my phone with Google Factory image but it was not completed because of my bootloader is locked. I don't know how i can unlock bootloader now. I used Wipe Data & Factory Reset option in Recovery Mode but it is also vain. Please help me how can I correct my phone.

Assuming you have adb/fastboot drivers correctly installed, you have to reboot to bootloader by pressing volume down + power and keeping them pressed until you see the bootloader screen. Then connect your phone to the PC and issue the following command from a command prompt:
fastboot oem unlock
Keep in mind that unlocking the bootloader will erase all your data, just like a factory reset, so backup everything first!

shivmahar said:
Dear friends,
I have LG Google Nexus 5 (Hammerhead D821(H) 32GB) model. Some days ago I tried to install Ubuntu Touch OS through UBports Software in my nexus 5 phone. But I forgot to enable USB Debugging first. So when I started the flash process and try to unlock bootloader, one time it show lock state unlocked. But In reality it was not unlocked. Because of this reason Ubuntu Touch OS installation is not completed and it corrupted my phone. Now I am unable to boot in android also. I also tried to re-flash my phone with Google Factory image but it was not completed because of my bootloader is locked. I don't know how i can unlock bootloader now. I used Wipe Data & Factory Reset option in Recovery Mode but it is also vain. Please help me how can I correct my phone.
Click to expand...
Click to collapse
perhaps it can help
https://forum.xda-developers.com/go...l-06-03-14-one-click-factory-restore-t2513937

shivmahar said:
Dear friends,
I have LG Google Nexus 5 (Hammerhead D821(H) 32GB) model. Some days ago I tried to install Ubuntu Touch OS through UBports Software in my nexus 5 phone. But I forgot to enable USB Debugging first. So when I started the flash process and try to unlock bootloader, one time it show lock state unlocked. But In reality it was not unlocked. Because of this reason Ubuntu Touch OS installation is not completed and it corrupted my phone. Now I am unable to boot in android also. I also tried to re-flash my phone with Google Factory image but it was not completed because of my bootloader is locked. I don't know how i can unlock bootloader now. I used Wipe Data & Factory Reset option in Recovery Mode but it is also vain. Please help me how can I correct my phone.
Click to expand...
Click to collapse
You can try with this toolkit http://www.wugfresh.com/nrt/
Surf the net in search of tutorial and info,there are also some videos on YouTube.

I already tried it but vain.
ilciumbia said:
Assuming you have adb/fastboot drivers correctly installed, you have to reboot to bootloader by pressing volume down + power and keeping them pressed until you see the bootloader screen. Then connect your phone to the PC and issue the following command from a command prompt:
fastboot oem unlock
Keep in mind that unlocking the bootloader will erase all your data, just like a factory reset, so backup everything first!
Click to expand...
Click to collapse
Dear Sir,
I tried to unlock bootloader with fastboot oem unlock command many times. When I used this command one time it shows unlocked but when I restarted bootloader it again shows locked.

Eh, this is not good. In my experience, this happens when the eMMC has gone bad, either faulty or write protected for some reason. I have investigated the issue and I have not found a solution yet... Even desoldering it and soldering it to a uSD custom PCB does not allow me to write to it... I am afraid you are stuck with a secretly bricked phone...

I don't know if you already tried all possible,just take a look at this thread.
https://forum.xda-developers.com/go...nexus-5-doesnt-boot-access-adb-t2521691/page3
Or even look at this,LG Flashtool.You don't need unlocked bootloader to flash.
https://forum.xda-developers.com/go...orial-how-to-flash-factory-images-lg-t2713833
The thread is quite old,but needed links are working correctly,i've just checked.