Experiment with u-root (u-root-builder booted from network, and tinygoized u-root)

[tlaurion]

https://github.com/linuxboot/u-root-builder now builds x86_64 compatible initramfs which could be applied atop Heads initramfs through network once #1384 is merged (edit: its merged)

some experiments could happen to have u-root downloaded from that project/somewhere else and applied on top of Heads in tmpfs/ramfs/squashfs on-demand and resume init from u-root.

Or

Once u-root is fully tinygoized, consider experiment with it as a possible future busybox replacement.

Reminder: host built binaries can be added under u-root as long as libc is also provided.
This could mean that all modules/* could be built from nix today and get rid of musl-cross-make as well.

[tlaurion]

Keep an eye on u-root/gobusybox#121