Getting an Apple Silicon Mac into Recovery Mode with no display.
I have an M1 MacBook Air that was given to me to recover data following a nasty incident with a friends ex boyfriend who turned it from a functioning MacBook into a boomerang. In several pieces.
I didn't get the display with the machine since it was toast—the T-CON board was still mounted in the top case and all the cables were totally ripped, hinges were still screwed in as well, just none of the rest of the display
Surprisingly, the thing still boots. I didn't even have to do anything. I can get into it no problem. Have recovered data for said friend.
But since said friend doesn't want it back, I wanted to get some use out of it. I need to get some pictures for the MacBook Data Recovery Guide I've been working on for Share Disk Mode steps and this is the only Apple Silicon Mac I have access to.
It will not show the startup options screen on the external display I have connected. It may be on the correct menu, but I would have no way of knowing since it doesn't output the primary display, only the secondary display in an extended setup. All I get is a black screen and mouse pointer if I manage to get the pointer on the second screen. Oddly, the internal display is still "detected" when I'm in OS. Maybe that's normal? But I don't even have the eDP cable connected.
Powering on never gets me an Apple logo even if it's booting, and I never see whatever was supposed to be on the primary display until it gets to OS where I have it set to mirrored mode.
I have tried various terminal commands I've found, which all errored as invalid (they all reference NVRAM which is handled differently on Apple Silicon Macs). I tried triggering lid closed signals via magnets. I've tried clicking blindly, and pressing keys in some combination that might make sense for selecting the Options button. But no change.
Please help me so I can help you.
UPDATE 03/19/2023: I have messed with this a whole bunch more, just for the sake of science, but still to no avail. I have seen others who mention this sort of behavior on Apple Silicon Macs. The internal display is still detected even when it is not present.
So I went into science mode. I powered it up and measured IPD_LID_OPEN_1V8. Which measured almost 1.8V on the nose. Neither of the hall sensors containing components are even connected.
Electrically speaking, I'm willing to bet it still thinks this display is detected. And it's open. But I'm not sure where the initial detect signal or logic comes from. So. I thought. I wonder what happens if I just break the line for the aforementioned Lid Open signal. So I removed RR203. This broke the path for this 1.8V signal to be transmitted elsewhere.
Now when I connected power to the board, it thinks the lid is closed, so it won't auto power on. I can probably force a shut signal by shorting that line after I'm sure the machine is on. I can get it to power on by shorting pads, but it acts weirder than it was before.
I will probably see what happens if you break some of the enable lines, or power rails for the display.
Is this a good question?