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5 Sep

How to Install / Flash Android Factory Images via Fastboot

Posted by Peter Teoh in technical. Leave a comment

Today I attempted flashing my Android Pixel 4a with Android Factory Images, and realize all the documentation on the web are not working for me. So what worked for me as documented below, is nowhere to be found anywhere else.

Method 1: https://developers.google.com/android/images?hl=en

And click on the “flash”, which may require you to go back and “prepare” the phone for flashing (3 requirements for flashing: 1. USB debugging must be enabled 2. OEM bootunlocking must be enabled 3. on the phone itself, you must “allow files transfer via USB permission to be enable”.)

End of the all the attempts: FAILED. This method of flashing does not work for me, inspite of so many ways of trying.

But after some trying, I did manage to get the “Not connected” to become “connected”:

And the Android phone itself will also be rebooted into bootloader mode, AND STUCK THERE like below (except the state is “LOCKED” bootloader stage). So question is WHO and HOW is it going to be “bootloader unlock” – the browser kept looping until error and the bootloader is still always locked. I think command line way of bootloader unlocking is much more reliable.

f5018023-283b-440a-928f-3d8a2d81c61e

So I attempted the next method.

Method 2: Download the images and flash it via command line.

Using the following link,

https://nerdschalk.com/flash-firmware-factory-image-google-pixel/

Does the procedure above worked? NO, it does not worked for me too. So what is the change?

Firstly no where it mentioned unlocking the bootloader, which for me is still in locked stage.

The answer (XXXXX is the serial number of the phone which appear in my “dmesg” output after connection) – assuming the current directory is the Android SDK where “fastboot” is located:

./fastboot flashing unlock -s XXXXX
< waiting for XXXXX >

Not working, as the command is perpetually waiting for input from the phone. So next:

sudo ./fastboot flashing unlock -s XXXXX
[sudo] password for tteikhua:
OKAY [ 0.030s]
Finished. Total time: 0.030s

Worked. The command “fastboot” need root permission to access the hardware.

Next problem is in Step 6:

First unpack the download from “factory images download”:

Then after ensuring “fastboot” and “adb” command are in the $PATH environment variable (because “flash-all.sh” script requires them) then the following:

As seen above, using a normal user, (non-root user) I kept getting “waiting for any device” message from “fastboot” command, which is essentially what “flash-all.sh” contained.

Flashing as a normal user is NOT working at all.

So “sudo” as root, and set the path to access all the “adb, fastboot” utililities as provided by Android SDK, and VIOLA the flashing start immediately (as root user):