Resolved Can't boot into recovery mode or boot from USB Installer

[Sharky II]

Hi all,

I have a 12-core 3.46GHz 4,1 -> 5,1 MP with RX 580 8GB and a PCIe AHCI boot drive, running Mojave 10.14.6 and Open Core 0.6.7 (Martin Lo config). I wanted to install Big Sur on a spare/empty SSD to test compatibility and have been running up against constant problems.

After creating a bootable USB Installer of Big Sur 11.2.2 the machine doesn't see it as bootable in OSX nor in the bootpicker. USB stick is formatted GUID/Journaled (Extended).

I tried to boot into recovery mode to see if I had set a firmware password or blocked booting from other drives (despite having no recollection of this) and first noticed that there are two recovery partitions (see attached pictre), one for 10.14.6, one for 10.13.6 (I don't have High Sierra partition anywhere AFAIK!).

When I choose either recovery mode or boot holding cmd + R, I get a loader screen for a minute or two (black and white new OpenCore style) and then the screen(s) just go black. I have left it for 10 mins and I don't get anywhere.

Can anybody advise any troubleshooting steps to get Recovery mode working, or at least to gather some more information?

Thanks,

Ed

 

[Sharky II]

Here are the results of diskutil list, in case you can see anything suspect. The main boot drive (256GB AHCI Samsung 951) is simply called 'Macintosh SSD'.

 

[Sharky II]

Resolved - unplugging HDMI connected monitor and leaving DVI connected ACD 30" worked.

Still not sure about why I can't create a bootable Big Sur installation, or why I have a 10.13.6 Recovery Mode partition, though!

 

[jetjaguar]

I have a 4,1 --->5,1 single cpu , nvme boot and rx 580 and I can not get into boot picker with holding option key .. also sometimes I have a boot screen and sometimes I dont. It is beyond frustrating. When I try to hold option or command R all i get is no signal on the monitor .. if I wait long enough sometimes it will just show the login screen eventually .. I dunno what to do. I have switched from using dp cables to hdmi and the same thing happens. I want to install windows on a spare drive but can never get to the boot option screen to install.

I am running Catalina but this happen on high sierra and mojave as well.