Ok, to clarify thing I think there is 2 kinds of locking problems here:
1) a Hard lock up That make you loose visual and or get green noise and that you must do a hard power down to recover from. This one I think they fixed it with the 30.1 update.
2) a soft lock up that will also make you loose visual with green noise(Therefore look very similar to number 1 problem), but this one you can still use the remote to change source, disable CMD etc.. but blindly. and disabling CMD or changing source for a different resolution/refresh rate combo will give you back a picture(sometime it is lock for all resolution and event with CMD off so it is not 100% repeatable pattern here). This one you can usee the power off button on the remote to close the projector. And it is still happening with 30.1.
Prior to updating to 30.1 I used to get both issues(took me a while to figure out it was 2 differents issues) But now since I updated a few month ago I only get issue number 2. Still anoying because most of the time that mean I still need to power down/power up to recover.
I suppose problem 2 is happing because something in the HDMI chain get screwed up(receiver, cable, etc). For me it is happening when I change resolution/Regresh rate on my HTPC or change source to my Roku or PS4 thru the receiver. interesting is the fact that it never happend on my Cable box witch is 1080p. as all other devices are 4k. I've just change my cable box for a 4k box this week so I will wait and see if I start getting the issue on my cable box also.
"Tempo is everything, perfection unattainable..."