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bootstrap-initrd

Linux initrd to bootstrap from a small binary seed git clone https://anongit.hacktivis.me/git/bootstrap-initrd.git/

make-img.sh (1445B)

    

  1. #!/bin/sh
  3. set -ex -o pipefail || exit 1
  5. SYSLINUX=/usr/share/syslinux
  6. KERNEL=/mnt/alpine/boot/vmlinuz-lts
  7. INITRD=bootstrap-initrd/x86_64+extras.cpio.gz
  9. ALPINE_ARCH=x86_64 ./make-initrd.sh
  11. FAT_PARTSZ=$(wc -c "$INITRD" "$KERNEL" | grep total | cut -f1 -d' ')
  13. # Add 25% for inodes, syslinux, …
  14. FAT_PARTSZ="$(printf '%s 1.25 * 512 / 512 * p\n' "${FAT_PARTSZ}" | dc)"
  16. rm -f bootstrap-initrd/x86_64.fat
  17. truncate -s "${FAT_PARTSZ}" bootstrap-initrd/x86_64.fat
  19. # FAT16 because otherwise syslinux throws an error:
  20. #   + syslinux -i bootstrap-initrd/x86_64.fat
  21. #   syslinux: zero FAT sectors (FAT12/16)
  22. mkfs.fat -D 0x80 -F16 bootstrap-initrd/x86_64.fat
  24. mcopy -i bootstrap-initrd/x86_64.fat "$KERNEL" ::vmlinuz
  25. mcopy -i bootstrap-initrd/x86_64.fat "$INITRD" ::x86_64.cpio.gz
  27. cat >bootstrap-initrd/x86_64.syslinux.cfg <<'EOF'
  28. DEFAULT linux
  29. LABEL linux
  30.   KERNEL vmlinuz
  31.   INITRD x86_64.cpio.gz
  32. EOF
  34. mcopy -i bootstrap-initrd/x86_64.fat bootstrap-initrd/x86_64.syslinux.cfg ::syslinux.cfg
  36. syslinux -i bootstrap-initrd/x86_64.fat
  38. mdir -i bootstrap-initrd/x86_64.fat -a
  40. rm -f bootstrap-initrd/x86_64.img
  41. truncate -s "$((2048 + ${FAT_PARTSZ}))" bootstrap-initrd/x86_64.img
  43. sfdisk bootstrap-initrd/x86_64.img <<'EOF'
  44. label: mbr
  45. start=2048, size=+, type=0x06, bootable
  46. EOF
  48. dd if="${SYSLINUX}/mbr.bin" conv=notrunc of=bootstrap-initrd/x86_64.img
  49. dd if=bootstrap-initrd/x86_64.fat conv=notrunc of=bootstrap-initrd/x86_64.img seek=2048 status=progress