A bare Linux kernel has no shell inside: it boots, prints, then panics
("No working init found" / "VFS: Unable to mount root fs").  Minimum for
an interactive CLI is ONE static binary as PID 1:

  mkdir -p rd/bin && cp busybox rd/bin/sh
  (cd rd && find . | cpio -oH newc) > rd.cpio
  qemu-system-i386 -kernel bzImage -initrd rd.cpio -nographic -append 'console=ttyS0 rdinit=/bin/sh'

"ours" = Linux 6.19.11 i386 tinyconfig + serial console, busybox embedded
INSIDE the image (CONFIG_INITRAMFS_SOURCE) — one 2.3 MB file, boots to ash.
Then type fredix: Unix V7 (1979) runs as a single static process
INSIDE this Linux (v7p, gcc -m32 -static; 'exit' returns to ash).
"generic + init" = the SAME Alpine kernel that panics bare, plus exactly that
recipe as init.cpio.gz (1.4 MB: busybox + fredix + 9-line /init) — and it boots to a shell.
Build recipe: fredix/tiny-linux.
Sources: kernel.org (GPLv2),
Debian busybox-static 1.38 i386,
Alpine 3.24 x86 vmlinuz-lts.