1️⃣ Download Stock Android for OnePlus Nord CE3 Lite

There is a possibility that you already have the .zip file on your system if you already been through the process of flashing a rooted ROM on your OnePlus device. If not then follow the steps

1. ⏬ Download an app called "Oxygen Updater" on any other android device from the Play Store, for example, Pixel 8 in my case.

   Download the full (stable) version with size > 5GB. You will have to Enable Advanced in oxygen updater app for this to work.

2. 📝Copying the file to mac.🔌Connect the Pixel phone to your machine (mac in my case). Assuming you have developer options enabled, you can copy the files somewhat like this.

   Go inside the shell

   $ adb devices 
   $ adb shell

   list the downloaded zip file

   OP5958L1:/sdcard/Download $ ls -ltr /storage/emulated/0/c43c92f604df4e81a321cabf966a32fc.zip  
   -rw-rw---- 1 u0_a260 media_rw 5673577777 2024-06-30 20:17 /storage/emulated/0/c43c92f604df4e81a321cabf966a32fc.zip

   
   COPY ZIP FROM ANDROID TO MAC

   (base) ~$ adb pull /storage/emulated/0/c43c92f604df4e81a321cabf966a32fc.zip ./
   
   /storage/emulated/0/c43c92f604df4e81a321cabf966a32fc.zip: 1 file pulled, 0 skipped. 33.1 MB/s (5673577777 bytes in 163.596s) (base) ~

2️⃣ Create .img files from .zip

Copy these two files into a folder

2. `https://gist.github.com/mkagenius/0516d6c184f503b6a906180f5d74f59f`
   
   (credit to original author - unfortunately lost the name)

3️⃣ Create a script to flash all of the images at once

First boot in fastbootd mode

Press Power and Vol Up button (10 secs) to shut down.
Press Power and Vol Down button (2 secs) to boot into fastboot.

Then do:

$ fastboot reboot fastboot

#!/bin/bash

for img in *.img; do
    partition_name=$(basename "$img" .img)
    fastboot flash "$partition_name" "$img" > /dev/null 2>&1
    if [ $? -eq 0 ]; then
        echo "- Writing $partition_name ... OKAY"
    else
        echo "- Writing $partition_name ... FAILED"
    fi
done

Running the Script

1. Save the script to a file, for example flash_images.sh.

2. Make the script executable:

   chmod +x flash_images.sh
   

3. Run the script:

   ./flash_images.sh
   

This script will attempt to flash all .img files in the current directory and output the result of each flash operation.

Some tips

1. To turn off the phone - Power + Vol Up for 10 secs

2. To start in fastboot mode Power + Vol Down for 2 secs

3. To go into fastbootd $ fastboot reboot fastboot

4. Remember, nothing should take more than a minute - if things remain same on screen for more than 5 minutes, then something is wrong!