I found out how to fix it the way I thought. Wanted to kind of explain how I did it. Please let me know, if I can make some kind of guide out of this, otherwise, feel free to copy my explanations and make one yourself.
I used Windows 10, you might have to adapt stuff for different OS’s.
!!! IMPORTANT !!!
This method it somewhat dangerous and may lead to data loss! Be careful!
Install VirtualBox. For me, I had to use an older version (4.3) as mounting a complete harddrive to a VM is forbidden by Windows 10 in newer releases.
Plug the harddrive in a spare SATA slot in your computer, but boot to your normal OS.
Open Disk Management on Windows (As an Admin user) and note down the Disk number you want to mount. I follwed this guide a bit, it has screenshots: https://www.markshardware.com/content/mount-raw-hard-drive-virtualbox
Open a console (Run as administrator)
Change Directory to Virtual Box. Standard installation folder is following command, adapt if neccessary:
cd C:\Program Files\Oracle\VirtualBox
VBoxManage internalcommands createrawvmdk -filename “D:\VM\drives\mydrive.vmdk” -rawdisk \.\PhysicalDrive3
Adapt the PhysicalDrive3 to whatever drive you noted before. Also save the file whereever you like by adapting the path.
All data on this drive will be lost! Be warned, take the wrong drive and you might fuck up your day!
Add the image for MineOS to the CD drive and click the button for adding a harddrive, choose existing and load up the previously created file.
Launch the VM and proceed with the installation. I chose the guided option without the LVM, as LVM didn’t work for me.
Be sure to let it install the GRUB bootloader, as you won’t be able to boot the OS from another Computer otherwise.
Shut down the computer, take the drive with MineOS out and put it into the PC you want to run MineOS. Start the computer. It should now simply boot into MineOS (Might have to change bootorder).
Feel free to ask me questions.