This article will be a re-release version of the topic.

UNLOCK BOOTLOADER WILL VOID YOUR WARRANTY AND ERASE DATA ONCE UNLOCKED, DO IT AT YOUR OWN RISK

Quote:
I strongly recommend you to install OST LA from there: https://drive.google.com/open?id=1n9…v8TjfeLc64AcYA

To install it properly, extract this pack and right click on setup.bat, run it with administrator privileges.

This guide should work on all qualcomm based Nokia Android Phones. For MediaTek based Nokia phones like Nokia 1 and 3, check related guide on Nokia 3 forum.

1. Backup all the data you have to either your PC or Cloud Drive. For Nokia 5 and 6 users with custom recovery, if you want to do data backup before unlocking, remove the lockscreen password before proceed.

2. Get your Phone’s model, Codename, IMEI, MEID and Serial Number. These are important for unlocking.

Take my Nokia 6 (2017) for example:
Model: Nokia 6 TA-1000 (Codename D1C)
IMEI and MEID can be obtained by dial *#06#.
Serial Number can be found in “Settings” – “About Phone” – “System Status”, or dial *#*#227#*#*. For example, Nokia 6 China Variant’s Serial Number starts from D1C.

3. Visit official bootloader unlock request website and input these info, and wait for response. The unlock key is a 256-byte file.

4. Turn on “Allow OEM Unlocking” in Development Settings, just in case.

5. Reboot to download (fastboot) mode. You should be familiar with how to enter download mode if you’ve tried OST LA.

WARNING! WARNING! WARNING!
IF YOU WANT TO KEEP YOUR PHONE IN WARRANTY, STOP RIGHT HERE!
IF YOU DON’T CARE ABOUT THAT, GO AHEAD.

6. Type these commands with your own fastboot:

Code:
fastboot flash unlock D:\unlock.bin
fastboot flashing unlock_critical
If you’re using the phone with AB partition scheme like Nokia 6 (2018), you’ll see a prompt that needs your confirmation.

<!>

By unlocking the bootloader, you will be
able to install custom operating system on
this phone. A custom OS is not subject to
the same level of testing as the original
OS, and can cause your phone and installed
applications to stop working properly.

Software integrity cannot be guaranteed with
a custom OS, so any data stored on the phone
while the bootloader is unlocked may be at
risk.
To prevent unathorized access to your
personal data, unlocking the bootloader will
also delete all personal data on your phone.

Press the Volume keys to select whether to
unlock the bootloader, then the Power Button
to continue.

_____________________________________________
DO NOT UNLOCK THE BOOTLOADER
_____________________________________________
UNLOCK THE BOOTLOADER
_____________________________________________

If you’ve flashed custom recovery before, the recovery will prompt you to type decrypt password, ignore that. Then tap 清除(Wipe) – 格式化 Data 分区 (Format Data Partition), type yes to proceed, then reboot your phone.

7. After your phone rebooted and done factory reset, enter Download mode again, then type these commands:
Code:
fastboot flash unlock D:\unlock.bin
fastboot oem unlock-go
You need to confirm again, If you’re using the phone with AB partition scheme.

8. Now your phone will reboot with bootloader unlocked, with the prompt like this:

Quote:
Your device has been unlocker and cann’t be trusted.
ID: D1CXXXXXXXXXXXXX

Your device will reboot in 5 seconds.

Or looks like this:

Quote:
Your device software can’t be checked for corruption. Please lock the booloader.
ID: D1CXXXXXXXXXXXXX

Your device will be continue in 5 seconds.

Or:

[!]

Your device software can’t be checked
for corruption. Please lock the
bootloader.

Visit this link on another device:
g.co/ABH

PRESS POWER TO CONTINUE
Your device will continue in 5 seconds.

ID: C1NXXXXXXXXXXXXX

8. The phone will enter the recovery to erase data.

If you’ve flashed custom recovery before, the recovery will prompt you to type decrypt password, ignore that. Then tap 清除(Wipe) – 格式化 Data 分区 (Format Data Partition), type yes to proceed, then reboot your phone.

9. Your phone will enter the system again.

After your phone get bootloader unlocked, and you’re able to get original boot, you can root your phone with Magisk.

Special thanks:

Everyone that unlocked the phone before this revision. Without your efforts, this can’t be possible.
@heineken78 for hints and providing correctly patched OST LA