Erratic booting on ASROCK VISION 3D

[tahitibub]

Hi,

I own an ASROCK VISION 3D computer on which I installed, a long time ago, Mavericks. I even wrote a tutorial about this installation here.

Now, I installed Sierra on this computer using Unibeast / Multibeast / Clover and the computer has got an erratic booting behaviour : most of the time, it resets itself before the end of the booting process, but sometimes it succeeds to boot.

Could someone help me to find what's wrong with this booting process ?

Regards.

 

[tahitibub]

I found something very strange : if I connect this ASROCK VISION 3D to a TV monitor, then macOS Sierra boots perfectly every time (but I've got another problem on the TV screen : overscan).

So, the booting problem could be related to my monitor (DELL U2414H) or to the GPU (NVIDIA GT425M) ?

Please help !