[Nothing Phone 2] Sh@kya:
Ok, So This Issue Is Caused Because Of "Driver Signature Verification Check" On Windows 10+

Now You Can Try To Disable That During BOOT OR Via Command Prompt, BUT Most Of The Time This Doesn't Work. (It Was Not Working For Me)

The Easiest Solution I Found Is To Boot Into Any Linux Distro [ LIVE Mode Will Do Just Fine, So No Need To Install The OS ] & Run The Commands From There. No Extra Drivers Required.

NOTE 00 : This Guide Is Meant To Be Used With Debian Based Linux (UBUNTU, KUBUNTU etc.), It Should Work On ALL Linux OSs, But The Initial Commands (01, 02, 03) Are Specific To Debian "apt".

NOTE 01 : Linux Live Distros Are Not Persistent, So You Have To Download & Install The "ADB & Fastboot" Tools [ Commands 01, 02, 03 ] EVERYTIME You Boot Into Fresh Linux LDs.

NOTE 02 : DO NOT Include The " | " When Pasting The Commands Below, I Just Added Them As XDA Was Not Formatting "Spaces" Correctly.

NOTE 03 : "Command 01" Is Usually NOT Required, I Just Do It Just Incase It Asks For A Sudo Password While In The Middle Of Something.

NOTE 04 : I Used A Generic USB A - C Cable To Do All These, So No Special Cable Required.

>>>> Instructions <<<<

-- I Booted Into "Kubuntu LTS" [ LIVE MODE ] [During Kubuntu BOOT, Select "Try Kubuntu" ]

-- Once Booted Into The Kubuntu Desktop, I Opened "Konsole" [ Terminal In Kubuntu ]

-- I Ran The Following Commands :-

01 > | sudo passwd root | [ Setup A Sudo Password (CAN BE ANYTHING) ]

02 > | sudo apt update |

03 > | sudo apt install android-tools-adb android-tools-fastboot |

[ Type "Y" When Prompted & Complete The Installation ]

==================

Now I Connected My Phone > Went Into Developer Options > Enabled "USB Debugging" & Enabled "OEM Unlock"

Then I Ran The Following Commands :-

04 > | sudo adb devices | [ Accept The Prompt On The Phone Screen ]

05 > | sudo adb reboot bootloader | [ The Phone Should Reboot Into Fastboot Mode ]

06 > | sudo fastboot devices | [ If It Returns A Response With A Device ID, Then Everything Is Working ]

07 > | sudo fastboot flashing unlock |

[ Will Give A Prompt On The Phone Screen, Navigate Using VOLUME Keys & Press POWER Button To Accept ]

Wait For The Process To Complete.

Now Run | sudo fastboot reboot | [The Phone Should Reboot & Do A Factory Reset.]

If You See A Screen With An Orange Exclamation Mark During Boot, Congratulations, You Have Successfully Unlocked Your Bootloader.

Once The Phone Has Factory Reset & Rebooted Successfully, Do The Initial Setup Again.

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=> To Install TWRP,

Download The Latest Image From This Thread Here On XDA.

Copy The Downloaded ".img" Image To The Desktop

Rename It To Something Short Like "1.img"

Right Click On It > Click On Properties And Note The Full Path Of "1.img" [ Should End With \Desktop ]

Open Konsole & Run "Commnads 01, 02, 03" (If On A Fresh LD)

Reboot The Phone Into "Fastboot" Mode. [If Phone Is On, Turn It Off And Press & Hold "Vol - & Power"]

Connect The Phone & Run "Command 06" To Check Fastboot Connectivity.

Now, Type The Following Commands :-

09 > | sudo fastboot flash recovery_a **\1.img | [ ** Is The Full Path To The "1.img" File]

10 > | sudo fastboot flash recovery_b **\1.img | [ ** Is The Full Path To The "1.img" File]

11 > | sudo fastboot reboot recovery | [ Phone Should Now Boot Into TWRP Recovery ]

===================

And Thats It,

You Can Now Disconnect The Phone And Reboot Your PC To Return To Windows.

You Can Do The Rest Of Your Phone Modifications Via TWRP. ;)

** If You Want To Relock The Bootloader And Return The Phone To Stock, You Can Check My Post Here.