Chosen Solution
I just got the screen replaced on my Early 2015 Macbook Pro and I noticed that I do not get backlight whenever I boot the computer. I can not see the Apple logo unless I shine a light through the back of the display. I also have an encryption password that I have to enter whenever I turn my computer on and I can not see any of that unless I shine a light through the back. When in the multi-boot picker I got no backlight as well. However, I can get backlight when I am fully in recovery mode and when I am fully logged in. The backlight works flawlessly when I am fully logged in and never flickers or anything. I have already tried to reset the SMC and NVRAM but that does not seem to fix the issue.
You’re likely having a problem with EDID of the screen you replaced. Unless you’re able to edit EDID data you’ll have to keep it as it is, no reset of sorts will fix the issue. Or you can replace the screen with a suitable one.
