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Screen flashes white for a second during boot

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7 hours ago, telepati said:
[mention=1303722]arsradu[/mention] Does OpenCore have a positive effect on this glitch?

Not that I know of. I tested some of the previous versions. But no...in my experience, it didn't make any difference.
 

Edited by arsradu

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Hi @Slice

 

About what you said above about MacOS emulating 10-bit color depth on 8-bit monitors.

 

So...Windows can set 10-bit color depth...but MacOS can't...? I'm not sure I understand. And...how is Windows doing it, if the monitor can't do 10-bit colors? I'm so confused. :))

 

I'm assuming the issue here is the switch from 8-bit to 10-bit. But...if it comes with 8-bit from BIOS, and if the monitor doesn't do "real" 10-bit (mine says "10-bit (8-bit+FRC)"; so I'm guessing that's not real 10-bit, so that's why this happens...?)), can we make it stay 8-bit in the OS, as well?

 

What's happening when there is no flashing at all? Is the OS not pushing 10-bit anymore...? Or how is it possible that, with the same hardware, sometimes it flashes and sometimes it doesn't?

 

 

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Actually I realized something when I got a 4K monitor. At the moment when this white flash happens it is cutting the signal of the video card for a millisecond then connect back and boot the hack. If this signal lost not happen I think this white flash won't happen.

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7 minutes ago, telepati said:

Actually I realized something when I got a 4K monitor. At the moment when this white flash happens it is cutting the signal of the video card for a millisecond then connect back and boot the hack. If this signal lost not happen I think this white flash won't happen.

 

ok...but why doesn't it always happen? Whatever it is. Why doesn't it always happen?

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Hi @Slice ! :) 

 

Is the Inject EDID feature working properly in Clover...? Is there any way to test that?

 

Cause...I extracted my EDID from Windows, edited it in MacOS using AW EDID Editor (set it to 8-bit instead of 10-bit) and added the resulted data into Clover under Custom EDID. Aaand...MacOS seems to ignore that. Still wants to use 10-bit. Ooor...maybe Inject Edid function doesn't really work right now? Which would also explain the lack of changes in my tests with different values of HorizontalSyncPulseWidth.

 

 

Screenshot_2019-11-06_at_21_27_52.thumb.png.aa123255106edefaeb3d61addb06275a.png

 

1681126850_Screenshot2019-11-06at21_18_26.thumb.png.d852d9183018a00126660fea798ffd02.png

EDID_LG_ULTRA_HD.rtf

EDID_test.bin

EDID_test.txt

EDID_orig.bin

Edited by arsradu

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4 hours ago, arsradu said:

 

ok...but why doesn't it always happen? Whatever it is. Why doesn't it always happen?

 

Exactly. Why this signal lost happening? Signal loss, give a white flash and come back and continue boot. No any sign on verbose btw. Also boot log doesnt give any clue. This is the most annoying problem.

Edited by telepati

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9 hours ago, telepati said:

 

Exactly. Why this signal lost happening? Signal loss, give a white flash and come back and continue boot. No any sign on verbose btw. Also boot log doesnt give any clue. This is the most annoying problem.

 

I meant...why doesn't the flash always happen? Cause it doesn't. It doesn't always flash. But it does flash 99% of the times.

 

If it's the same cause, why isn't the same effect all the times?

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12 hours ago, arsradu said:

 

I meant...why doesn't the flash always happen? Cause it doesn't. It doesn't always flash. But it does flash 99% of the times.

 

If it's the same cause, why isn't the same effect all the times?

 

But, it does always happening to me. :cry:

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An interesting fact. It doesn't occur if the display is a secondary display. But with a secondary display, you also have no signal before the OS.

 

So, basically, if we have signal in preboot, we have a flash when switching to the OS. If we don't, we also have no flash. Why is that? Can't it just initialise with no flash, just like it does when there is no signal until the OS kicks in?

 

By the way, any idea how did this guy manage to get a boot screen on what looks like a MacPro4,1 with a Sapphire Pulse RX 580 8GB?

 

Cause, that raises two questions:

1. is it still necessary for whatever is Clover doing to get us that boot screen?

2. would that fix this annoying issue?

 

I've noticed the boot was pretty long... Not sure if that's part of the "fix" and he didn't include an explanation of how to do it. But cool nonetheless!!

 

By the way, if you wanna test the "secondary display" thing I mentioned before, you don't actually need two monitors. Just one monitor and two cables. :D 

 

EDIT: looks like in this case, the card has been flashed with a custom ROM or something.

 

 

Edited by arsradu

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