Preparations before upgrade
First, make sure your mobile phone is unlocked and USB debugging has been enabled.
Configure your computer to upgrade the environment (skip this step if you have already configured it) and decompress the file.
Copy adband fastboot.exe in the name to c:/windows/system32
Copy all files whose names contain adb to c:/windows/system.
Click to download adb and fastboot
Then you need to prepare the Android L upgrade image, which can be downloaded from Google's official website.
Upgrade process
Connect your Nexus5 to your computer
Enter the "adb reboot bootloader" command in the CMD mode of the computer to enter the bootloader mode.
Open and decompress the downloaded upgraded image tgz package as a compressed file, and then decompress the tar file.
Open the extracted folder and double-click flash-all.bat to start upgrading
Friendly reminder: Android can be upgraded to Android in theory, but the upgrade methods for each mobile phone are different, so I will not introduce them one by one, you can view the instructions on your mobile phone.
