Catalina + Windows 10 dual boot, boot failure

[anoopkr]

Hi all,
I have successfully installed Catalina on my PC (970A-DS3P, FX6300, Quadro K420), basic things work well. But it is not booting without installer USB, I have followed detailed instructions (Copy USB EFI folder to SSD EFI partition) but did not work. I have Windows in another SSD and a couple of other HDDs for data storage. Is this Wndows installation culprit ?

 

[Edhawk]

When you created the EFI folder did you do so in Legacy mode, i.e. with a 'Boot' file located alongside the EFI folder on the USB's EFI Partition? It would look like this in Finder.

Legacy boot mode setup

If you fail to copy the 'boot' file to the SSD's EFI Partition the system will not boot. As the 'boot' file activates the settings in the EFI, without it the EFI does nothing.

Check the EFI Partition on the USB and see if both parts of the legacy boot were copied to the SSD's EFI Partition.

 

[anoopkr]

Hi edhawk,
Thaks for your reply, i created usb in uefi mode, using gibmacos utility. Its boot partition contains EFI/BOOT and EFI/OC folders.
Tonight I shall remove the Windows disk and see. Will let you know for sure.
Regards
Anoop

 

[anoopkr]

Update:
My speculation was right, the moment I unplugged Windows ssd, opencore loaded as usual and booted in to mac. Now i have to find a way to dual boot.
USB 2.0 not working, as well as wifi (mt7601).

 

[Edhawk]

You need to have Windows installed in UEFI mode, not MBR/Legacy mode to work with OpenCore.

Creating the Windows installer with Rufus and selecting GPT over MBR will create a UEFI installer. OpenCore will then work with your macOS and Windows installs.

Rufus - Create bootable USB drives the easy way

Rufus: Create bootable USB drives the easy way

rufus.ie

I use this installation method with Windows 10 and Windows 11 installs on all my dual-boot Hacks.