Mirroring display in Recovery Mode with faulty lid sensor and LCD?

Question

Today I bought a 2017 Macbook that has a water damaged LCD and a faulty closed-lid sensor. My intention is to factory reset it and use it as a build system (i.e. develop my app on my desktop, then remotely connect into the machine to compile / distribute).

When in MacOS, I can ⌘ Command+F1 to mirror to an external display, but obviously that doesn't work in recovery mode. One suggestion was to boot to recovery, then simply close the lid to make the external display the primary display, but with a faulty "lid closed" sensor, I can't do that.

Another suggestion was to close the lid, then run a fridge magnet over the corner of the unit to activate the closed-lid sensor. I tried this, but it just puts the unit to sleep, and I need to open the lid to start it back up.

Someone else suggested attempting to drag the window over from one screen to another, but I tried a bunch of times and had no luck because it's a bit of a stab in the dark to hit something that thin.

I have a dock at work that I intend to try (so I can close the lid, do the magnet, then use an external keyboard to try and wake the device), but until I can get to it, I'm wondering if there's a way to mirror the display, or at least move the window so I can proceed with reinstallation of MacOS?

Answer 1

The solution that worked for me, and was suggested to me by someone over on Reddit, is to remove the bottom of the Macbook and unhook the LCD cable. Once I did that, the external screen acted just like the internal screen. I could see the Apple logo, the recovery mode welcome screen and all that jazz.

There's teardown instructions over on iFixit, but I didn't need to follow all the steps. I just needed to undo the screws (steps 1-8) and unhook the trackpad cable (steps 9-11) to get the case open far enough to unhook the LCD cable (steps 19-23)