AArch64 Support

In the Readme file I found information that Towboot has i686 and x86_64 support. Does it also have aarch64 support?

[YtvwlD]

It does not, at the moment at least.

The reason is quite simple: Multiboot 1 (which is the only Multiboot version towboot supports at the moment) is only specified for x86. Multiboot 2 added support for MIPS, but UEFI does not.
So, officially, x86 is the only platform where a Multiboot-compatible bootloader for UEFI can work. And we only support 32-bit kernels at the moment.

Unofficially, though, there have been ports of Multiboot to arm and aarch64 and of UEFI to MIPS. (I haven't really looked at any of them.)

So yes, this would be theoretically possible, although the result would probably be really niche. Are there any Multiboot-kernels for ARM? And I currently lack the knowledge of ARM internals to pull this off.

Adding ARM support would not be that difficult though, I suppose. The last part of PreparedEntry::boot would need to be split off and put behind a #[cfg].

If you'd be interested to do this, I'd be happy to review your pull request. :)