In the previous guide, we saw how Google Pixel 3 and Pixel 3 XL can get TWRP recovery support. Today we will see instead how to get the Root permissions on the Google Pixel 3a so that you can have access to all the files of the operating system and finally have Android completely free to be changed at will in every part. After unlocking the Bootloader, you should find yourself with Android returned to factory status, you can then proceed to the Magisk Manager installation to get the Root permissions. Let's see in this guide how to proceed.
Once you have unlocked your Bootloader, you will need to download the factory image for your specific device model. You will need to use a computer for this phase so that you can do things easier. Click on this link to download the latest download for Pixel 3a or 3a XL. Scroll down the linked page to access the list of downloadable image files and make sure it is the right version for your device. The factory images are large because they include the entire Pixel operating system, but for this guide, to get the Root permissions on the Google Pixel 3a, only one particular file is required contained within the package.
After completing the download of the entire factory firmware package on the computer, it is necessary to extract the folder to a desired location on the PC. Once extracted for the first time, look for the only ZIP file in the folder that starts with "image" and then extract the file inside the current folder to reveal all the system files. Since you need to take only one image file from the group, you need to look for one called "boot.img". Then proceed to connect the phone to the computer using a USB data cable. Now all you have to do is transfer the boot.img image file from your computer to the "Download" folder on your phone.
To be able to get the Root permissions on the Google Pixel 3a, you must now download the Magisk Manager apk file and install it on the device as you would with a normal application. Being a small file, the download should not take so long and once downloaded you have to do nothing but proceed with the installation. If you use a browser like Chrome on your phone, you may be asked to give the browser the appropriate permissions to install the Magisk Manager application. Just tap "Settings", then enable the switch for the "Allow from this source" option. Tap the Back button once, then press "Install".
Now you have to patch the boot image, which you can do from the main menu of the Magisk Manager application, by tapping "Install", then tap "Install" again to see a new set of options. Select the option "Select and apply a file" (Select and patch a file) and then allow multimedia permissions when asked by tapping "Allow". From the file manager that opens, you need to click on the menu icon located in the upper left of the screen, then select "Download". Select the "boot.img" file, then Magisk will start the process which will be completed in about a minute. Once you have finished applying the patches to the file, go ahead and touch the back arrow to complete the process.
Now that you have the patched "boot.img" file you need, to get the Root permissions on the Google Pixel 3a you will need to use a quick command via ADB and Fastboot to send the file to your phone at the system level. You will need to download the separate package of the Google SDK platform, where you will find everything you need inside.
At this point, you will need to transfer the patched boot image you obtained via Magisk. The file should have the name "magisk_patched.img" and should be in the same "Download" folder where the original file was located. It then starts the phone mode Fastboot to be able to transfer the boot image file edited on your system. Long press the power button, then tap "Turn off" to turn off the phone completely. After the phone is switched off, simultaneously hold down the power button and the volume down button until the main Fastboot Mode menu is displayed. Make sure your phone is connected to your computer, so leave everything like this to go to the next step in this guide.
Now you have to open a command window on Platform-Tools. The phone should be on the main Fastboot mode screen. It is almost ready to receive the correct command to send over the boot image file with patch to get Root permissions on the Google Pixel 3a. You will need to open a command window in the Platform-Tools folder so that the Fastboot command can be sent to the phone.
Then open ADB and Fastboot and type the following command followed by the Enter key: fastboot flash boot magisk_patched.img
Once the patched boot image is properly installed, you will need to press the volume buttons a few times until you reach the "Start" option in the Fastboot Mode screen menu. Press the power button to confirm your choice, then the phone will restart. After rebooting the phone, go back to the Magisk Manager application, then make sure you have both green check marks regarding "The latest version" and "Installed version". You should also tap the arrow next to "Tap to start SafetyNet check" (Tap to start SafetyNet check) to make sure you pass Google's security check.
That's all for this guide to get the Root permissions on the Google Pixel 3a. If everything has been done correctly you should finally have access to all the files of the Android operating system, without any limit.