Critical error on lg g2 fixed All Version (New & Easy Method): [LG-G2] Unbrick (qhsusb_bulk)-NO Recovery mode, No download mode, fastboot mode started Fixed

First of all i must thank @Shelnutt2 from lg-g2 irc channel who helped me to unbrick my phone and get it back alive. The whole process described bellow came from him.

Description of the problem:

Your LG G2 D802 is living this situation:
1- Rooted and got OTA
2- No Download mode
3- No recovery mode
4- Secure booting error
5- LG detected as qhsusb_bulk in device manager
6- When you boot your device it shows only LG logo with secure booting error, then the screen goes black while your phone is still on.
7- Other symptoms

The only solution for you is the following.

I'll explain the solution for an LG G2 D802 10a, then you can apply it for your device model by downloading the appropriate files.
You will need to use linux.
Ubuntu is good enough to make the job. You can use a virtual machine, live cd or a bootable usb stick.

So lets start.

Files to download from here
VERY IMPORTANT!!!!!!!
You must use the img files that correspond to the ROM you have installed before getting the problem to avoid breaking your phone. The link above is for 10b_EUR_16G firmware version. So don't use those files if your firmware version was not that one. Instead you should look for img files corresponding to the current version installed in your phone. If you don't know what version you've installed then don't use this method because you will break your phone.
1- sbl1.img
2- aboot.img
3- rpm.img
4- tz.img
5- openrecovery-twrp-2.6.3.2-g2d802

Thanks to @sabooakhte who has shared his experience:

Quote:

IMPORTANT: NEVER FLASH ORIGINAL RECOVERY.IMG TO THE RECOVERY PARTITION!!!

Now just boot into ubuntu and plug your LG G2 to the computer.

Put the downloaded files in the desktop or wherever you want. You just need to know the path to your files.
unplug any other usb device except your mouse, keyboard and lg g2.
Open terminal in ubuntu then type:

Code:

ls /dev/sd*

It should return something like this:

Quote:

/dev/sda /dev/sda1 /dev/sda2 /dev/sda5
/dev/sdb1 /dev/sdb2 /dev/sdb3 /dev/sdb4
/dev/sdb5 .......... /dev/sdb36

In this case your device is detected under sdb. you may have it under sdc. just look for the biggest number, in this case /dev/sdb36 so it is sdb.

Linux keeps poping up error message "unable to mount..."? follow this solution by @priority3

Quote:

Originally Posted by priority3

You can stop the "unable to mount..." error messages from popping up by disabling
the automount feature of Ubuntu.
"To enable or disable automount open a terminal and type dconf-editor followed by the [Enter] key.
Browse to org.gnome.desktop.media-handling."

now, according to the result of the first command type the following:

Code:

gdisk -l /dev/sdb

you will get result:

Code:

Number  Start (sector)    End (sector)  Size       Code  Name
   1           32768          163839   64.0 MiB    0700  modem
   2          163840          165887   1024.0 KiB  FFFF  sbl1
   3          165888          166911   512.0 KiB   FFFF  dbi
   4          196608          197631   512.0 KiB   FFFF  DDR
   5          229376          231423   1024.0 KiB  FFFF  aboot
   6          231424          233471   1024.0 KiB  FFFF  rpm
   7          262144          294911   16.0 MiB    FFFF  boot
   8          294912          296959   1024.0 KiB  FFFF  tz
   9          296960          296961   1024 bytes  0700  pad
  10          327680          333823   3.0 MiB     FFFF  modemst1
  11          333824          339967   3.0 MiB     FFFF  modemst2
  12          339968          339969   1024 bytes  FFFF  pad1
  13          360448          393215   16.0 MiB    FFFF  misc
  14          393216          458751   32.0 MiB    0700  persist
  15          458752          491519   16.0 MiB    FFFF  recovery
  16          491520          497663   3.0 MiB     FFFF  fsg
  17          524288          525311   512.0 KiB   FFFF  fsc
  18          525312          526335   512.0 KiB   FFFF  ssd
  19          526336          526337   1024 bytes  FFFF  pad2
  20          526338          527361   512.0 KiB   FFFF  encrypt
  21          557056          573439   8.0 MiB     0700  drm
  22          573440          589823   8.0 MiB     0700  sns
  23          589824          655359   32.0 MiB    FFFF  laf
  24          655360          720895   32.0 MiB    FFFF  fota
  25          720896          786431   32.0 MiB    0700  mpt
  26          786432          787455   512.0 KiB   FFFF  dbibak
  27          787456          789503   1024.0 KiB  FFFF  rpmbak
  28          789504          791551   1024.0 KiB  FFFF  tzbak
  29          791552          791567   8.0 KiB     FFFF  rct
  30          819200         6488063   2.7 GiB     0700  system
  31         6488064         7733247   608.0 MiB   0700  cache
  32         7733248         7897087   80.0 MiB    0700  tombstones
  33         7897088         7929855   16.0 MiB    0700  spare
  34         7929856         8028159   48.0 MiB    0700  cust
  35         8028160        30703615   10.8 GiB    0700  userdata
  36        30703616        30777310   36.0 MiB    0700  grow

We will be interested by lines marked by red color here. those lines show us the partitions numbers of each file we have downloaded at the begining.
I'm talking about
1- sbl1.img
2- aboot.img
3- rpm.img
4- tz.img
5- openrecovery-twrp-2.6.3.2-g2d802

in our case the sbl1.img is located under sdb2
aboot.img under sdb5
rpm.img under sdb6
tz.img under sdb8
recovery under sdb15

now be careful and try to make it the right way.
we will use dd commands to push img files inside the right partitions.
So lets start:

if youare not logged on as root in ubuntu just open terminal and type

Code:

sudo -i

then type your password

now you must be under root access.

then type the following dd command:

Code:

dd if=/home/med/Desktop/sbl1.img of=/dev/sdb2

i put files in the desktop, so the path to the img files for me is /home/med/Desktop/. just replace this path by the appropriate path to your files. one done you will get some information about the file size you pushed and maybe time of the operation.

keep doing the samething for the other files:

Code:

dd if=/home/med/Desktop/aboot.img of=/dev/sdb5

dd if=/home/med/Desktop/rpm.img of=/dev/sdb6

dd if=/home/med/Desktop/tz.img of=/dev/sdb8

dd if=/home/med/Desktop/openrecovery-twrp-2.6.3.2-g2d802 of=/dev/sdb15

Once you finish just reboot your phone, if you did things as described you must boot into twrp recovery.

now just use twrp to flash your ROM and follow this tutorial to reboot into your ROM
http://criticalerroronlgg2fixing.blogspot.in/2017/01/fix-installed-twrp-and-now-youre-stuck.html