HTC One M7: screen won't turn on again, only after reboot. What could the problem be?

A

AC Question

HTC One M7: screen won't turn on again, only after reboot

The screen of my HTC One M7 just won't turn on again once it's been turned off. The lock screen won't show up, although the home/back buttons do light up, and the lower right part of the screen is white/light gray. If I reboot the phone, then everything works perfectly until the screen is turned off.

This had been going on for about a year now, but it happened only randomly (about twice or thrice every day). I have recently installed CM 12.1, but I don't think that's causing it, since I have the same problem if I boot into recovery. Other than that, I've cracked my screen a couple of months ago and had it repaired, and the problem has been happening ever since.

Any help is much appreciated!