Boot High Sierra from USB Drive on Macbook Air 2019

[gegy]

Hey guys, i need your help please.

I have created a bootable USB drive with High Sierra on it. I first made an Bootable installer on the disk, then took the disk to my iMac 27" late 2009 and booted the installer. Then i installed mac os high sierra on the external USB drive.
Now i want to boot from that drive (high sierra is installed) on my Macbook Air 2019 (with T2). So i enabled boot from external disk in recovery boot. Now when i press the option key i can see the disk and select it for booting from. But the Macbook Air does not boot from the disk into High Sierra. I boots in recovery mode.
Is it possible to boot into High Sierra from the external disk?

 

[reppresident]

i believe its not possible to boot an os earlier than that who came installed

 

[gegy]

I guess you are right, but i can not find any info about that circumstance.

 

[gegy]

For better understanding why i want to do that: I want to prepare the installation for my mac mini 2010 before i swap the old disk out and put the new one in.
Maybe it is possible to run the os in virtual box?

 

[sdfox7]

For better understanding why i want to do that: I want to prepare the installation for my mac mini 2010 before i swap the old disk out and put the new one in.
Maybe it is possible to run the os in virtual box?

@reppresident is correct. You cannot boot any earlier than Mojave 10.14 due to the firmware.

2015/2017 MacBook Air is the last model that can boot Sierra/High Sierra. You can try Parallels but it's not free.