How can I DIY firmware upgrade my projector and what should I pay attention to?

The latest firmware update improves the rainbow effect issue, and if you're interested in resolving this, here is a guide to updating the firmware yourself.
 

• Can I update the firmware on my own? 
  Of course, it's a really simple process. You can do it yourself easily. Just follow the step-by-step instructions below or check the how-to video here:

1. Please download the latest firmware

2. Unplug the power cord. 

3. Long press” power” and “source” key and plug in the power cord at the
    same time.

4. Three flashing red lights blink simultaneously on the front of the projector.

5. Connect a laptop or desktop PC to the projector via USB-A.

6. Double click the firmware file, which starts the update process. This takes 4-

    6 minutes to complete.

7. The update process will be completed when you see a “DEVICE NOT

    FOUND” pop up message.

8. Power on the projector until the power indicator goes back to standby mode

    (steady orange light) 

9. Check the firmware version (go to menu-> information->firmware version)

10. If the process doesn't complete as expected, please unplug the power cord
     and press the “up” and “down” keys at the same time then plug in the
     power cord and the system will reset so you can try the update again from
     step 6.

• How long will the entire installation procedure take?
  The installation procedure will take around 5 minutes. 

• What equipment is required for the installation?
  One USB-A to USB-A cable
  Laptop or desktop computer with Microsoft OS. 
  Meanwhile, it’s not compatible with MAC OS devices. 

• Can I read the USB-A via the USB-C to USB-A cable?
  Only a native USB-A port can be used to read the file.

• I read somewhere that a user had to ship the item back to your service center to get the update. Why?
  In a previous Reddit post, we asked the user to return the item for the firmware update.  Now, the firmware update is currently and conveniently available for anyone to easily install via The BenQ Website. 

• If the upgrade failed, can I recover the download?
  Yes, please unplug the power cord and press “up” and “down” keys at the same time then plug in the power cord, projector will be reset and you can try to upgrade the firmware again

• If I still have a question about the installation, how can I reach the service center?
  Please contact BenQ Service Center for further assistance.