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The Dell OptiMac Big Sur/OpenCore Thread - For 7020/9020 Optiplex Desktops

My Big Sur installation was successful. However, I only have the option to enter it through the Preboot partition. There are 3 partitions on the disk that I installed, any reason for this to happen?
 
What to do when the installation is within a Container like this and only boots Big Sur when "Preboot" is selected at the Opencore Bootloader? There are an update partition too and I really dont imagine how to proceed with it.
Thank you for the guide. All the hardware is perfectly working.

Screen Shot 2020-09-17 at 18.35.24.png
 
What to do when the installation is within a Container like this and only boots Big Sur when "Preboot" is selected at the Opencore Bootloader? There are an update partition too and I really dont imagine how to proceed with it.
Looks like something went wrong with your Big Sur installation. You should be seeing the Big Sur SSD as well as the
Big Sur SSD - Data partition. You can see the greyed out disk5s5 where it should be.

Screen Shot 5.jpg


It looks like this on my Catalina SSD:

Screen Shot 2020-09-17 at 6.08.33 PM.png

"Catalina" is not greyed out, it's where the read-only operating system resides. Your Disk Utility screenshot doesn't show that. It should have Big Sur SSD and Big Sur SSD - Data too, but it doesn't.

It looks like you have four separate SSDs connected to your Optiplex. Try a clean reinstall of Big Sur. This time disconnect all the other SSD drives when performing the install. That should make it much less complicated and give you a better result.
 
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Thank you. I Will try.
 
I did a fresh install without any drives attached and happens the same above with my partitions.
And only boots with a "Preboot" option.
Can anyone check my attached EFI?
 

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  • EFI-Opencore-18-9-2020.zip
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I did a fresh install without any drives attached and happens the same above with my partitions.
And only boots with a "Preboot" option.
Read these posts and give it a try.
 
Read these posts and give it a try.
Thanks a lot. Theres a Big Sur option at my OpenCore menu now.
My Mojave partition works with it, but Catalina not. Will be other nice party with a beta bootloader.
Honestly, I prefer the Clover days... but OpenCore must be the future.

Edit: Theres a best option to boot Mavericks with opencore or it cant be done?
 
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I noticed that the optiplex 3020 excluded from the conversation!
The 7020/9020 are both Q87 chipset boards. Really no difference between them. If the 3020 were the same chipset it would be included. It's got the H81 chipset, Dell did this to cut costs. This thread doesn't support those models. The BIOS is obviously different for the 3020s. The MSR unlock process and the other changes made with modGRUBShell.efi could brick the motherboard. That's the primary reason I didn't include those. Sound like a valid enough reason ?

For anybody that didn't see post number 6:

Screen Shot 22.jpg
 
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