Everything works flawlessly when the screen is installed – all apps and configurations work as they are intended. However, once the screen is removed, the phone doesn’t work. On a pixel 3a I was able to attach just a ribbon cable for the screen without the actual screen, and when I pulled it up in airdroid, it would only display a condensed screen about 1/3 the height. On the Pixel 3 it doesn’t load up at all.
I’ve connected the phone to my computer with USB debugging enabled. Without the screen it shows up in the devices list. But with the screen it doesn’t even show up in the devices list. The only way to make the phone operational is to remove the battery cable then restart the phone. About 30% of the time it displays a message upon boot "This device failed to boot, do you want to factory reset", with an option of "yes" and "reboot" (selectable through the volume and power buttons).
Also of interesting note, if I power on the phone without the digitizer connected, I can use AirDroid just fine, but it won’t register my clicks on the remote view screen. Which leads to believe the phone is registering the hardware of the screen and digitizer upon boot.
If I disconnect the digitizer and LCD after the phone is booted up, I can attach them both and it’ll work. It’s just when they’re disconnected from the phone during the initial boot phase.
I tested this with a Galaxy S8 previously, and that phone worked just fine without the screen attached, and ran fine that way.
Does anyone have any ideas on how to "register" the hardware correctly? I’m not certain that’s what’s happening, but it appears to be something with the hardware not registering correctly, or something like that. What’s odd, is that it doesn’t work even with the ribbon cables attached. It requires the full screen to be connected to the ribbon cables.
I’ve searched up and down google, but there doesn’t appear to be much information available on this, as it appears to be a very specific problem which not many people encounter.