For deployments where China is not preferred in system install/boot root of trust, standalone grub2 can boot multiple ISOs and VHDs. Sample configs for grub2 I

For deployments where China is not preferred in system install/boot root of trust, standalone grub2 can boot multiple ISOs and VHDs. Sample configs for grub2 ISO boot, e.g. USB or secondary disk partition for system recovery, https://news.ycombinator.com/item?id=38663958 https://news.ycombinator.com/item?id=38663958 There is dedicated hardware to emulate optical drives, e.g. Korean IODD sells SSD enclosures to emulate up to 4 virtual optical drives in parallel, mapped to ISOs or VHDs. As a standalone device, this keeps untrusted emulation code away from the system CPU. The output of that untrusted code could be verified, e.g. by hashing the emulated ISO.