Virtually Attend FOSDEM 2026

Netboot without throwing a FIT

2026-02-01T09:20:00+01:00 for 00:20

For years, Ahmad’s ideal has been simple: unpack a rootfs on a server, mount it over NFS (or usb9pfs), boot directly into it, and everything just works™.

But as secure boot becomes the default on many embedded systems, squeezing in a network-booted kernel is getting harder and often falls outside the supported boot flow entirely.

Fortunately, some recent improvements in the kernel build system pave the way for a far less invasive netboot setup. This talk gives a quick tour of the key pieces:

  • The image.fit target for arm64 introduced in v6.10
  • The modules-cpio-pkg target introduced in v6.19
  • Initramfs that bind mounts its modules over the rootfs
  • Optional concatenation of multiple initramfs in the bootloader

In ten minutes, you’ll see how these changes raise the netboot FITness of Linux, so you can keep printk-debugging to your heart’s content.

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