LG D820 switch to seral fail

I have been trying to unlock and repair this phone but I keep getting the same error can anyone help



I have



Restore the phone, I am using a laptop, no other devices connected, restart laptop please help



Welcome to Octoplus/Octopus Box LG Software version 1.8.6

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Checking data...OK

Platform: LG Qualcomm

Selected port: COM4

Selected model: D820

Reading info...

Initializing ADB...OK

Waiting for phone...OK

Model ID: Nexus 5

Firmware version:

Kernel version: 3.4.0-g88fbc66 (android-

build@vpbs1.mtv.corp.google.com) (gcc version 4.7 (GCC) ) #1 SMP

PREEMPT Mon Oct 20 22:18:31 UTC 201

Android version: 5.0

Hardware: Qualcomm MSM 8974 HAMMERHEAD (Flattened Device Tree)

ARMv7 Processor rev 0 (v7l)

Initializing ADB...OK

Waiting for phone...OK

Switching to Fastboot mode...OK

Unlocking Bootloader...

Bootloader is unlocked.

Writing Bootloader...OK

Please, wait while the phone will turn on and press "Ok" button.

Trying to enable Diagnostics ports...

Initializing ADB...OK

Waiting for phone...OK

Checking root access...

Phone is already rooted.

Diagnostics ports are enbled!

Switching to Serial Port...

Failed!

--------------------------------------------------------------------------------

Platform: LG Qualcomm

Selected port: COM4

Selected model: D820

Reading info...

Initializing ADB...OK

Waiting for phone...OK

Model ID: Nexus 5

Firmware version:

Kernel version: 3.4.0-g88fbc66 (android-

build@vpbs1.mtv.corp.google.com) (gcc version 4.7 (GCC) ) #1 SMP

PREEMPT Mon Oct 20 22:18:31 UTC 201

Android version: 5.0

Hardware: Qualcomm MSM 8974 HAMMERHEAD (Flattened Device Tree)

ARMv7 Processor rev 0 (v7l)

--------------------------------------------------------------------------------

Checking data...OK

Platform: LG Qualcomm

Selected port: COM4

Selected model: D820

Reading info...

Initializing ADB...OK

ADB Server was found. Trying to kill...

Waiting for phone...OK

Model ID: Nexus 5

Firmware version:

Kernel version: 3.4.0-g88fbc66 (android-

build@vpbs1.mtv.corp.google.com) (gcc version 4.7 (GCC) ) #1 SMP

PREEMPT Mon Oct 20 22:18:31 UTC 201

Android version: 5.0

Hardware: Qualcomm MSM 8974 HAMMERHEAD (Flattened Device Tree)

ARMv7 Processor rev 0 (v7l)

Initializing ADB...OK

Waiting for phone...OK

Switching to Fastboot mode...OK

Unlocking Bootloader...

Bootloader is unlocked.

Writing Bootloader...OK

Please, wait while the phone will turn on and press "Ok" button.

Trying to enable Diagnostics ports...

Initializing ADB...OK

Waiting for phone...OK

Checking root access...

Phone is already rooted.

Diagnostics ports are enbled!

Switching to Serial Port...

Failed!

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