loader being a Mach-O executable that iBoot will jump to. After that everything is for you.
Note: the command should be executed from macOS 1 True Recovery (hold the power button for the first few seconds at boot up) to downgrade the security policy.
the MBA of @marcan42 seems l̵i̵k̵e̵ ̵I̵n̵t̵e̵l̵ ̵b̵a̵s̵e̵d̵,̵ ̵i̵f̵ ̵M̵1̵ ̵i̵s̵ ̵a̵v̵a̵i̵l̵a̵b̵l̵e̵ ̵t̵o̵o̵ (it's M1 acturally) it means we can boot other OS on M1?
As far as I'm aware the tool (probably Disk Utility I think?) on macOS that allows you to replace the bootloader etc now supports non-macOS replacements.
loader being a Mach-O executable that iBoot will jump to. After that everything is for you.
Note: the command should be executed from macOS 1 True Recovery (hold the power button for the first few seconds at boot up) to downgrade the security policy.