How to generate bootable USB keys with simple-cdd

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simple-cdd is a lovely piece of software that builds a custom D-I image with the package selection and preseeding of your choice.

Today I was asked to build a bootable USB key with the simple-cdd image. Here is how; the general case is described in the d-i manual:

General USB key preparation:

  1. download vmlinuz and initrd.img from hd-media
  2. apt-get install syslinux mtools mbr
  3. Partition the USB key as needed (from now on, I'll assume the usb key is in the device /dev/sdb1)
  4. Format it as FAT: mkdosfs /dev/sdb1
  5. Put the boot loader in it: syslinux /dev/sdb1
  6. Put the MBR in it: install-mbr /dev/sdb
  7. Mount it: mount /dev/sdb1 /mnt
  8. Copy kernel and initrd: cp vmlinuz initrd.img /mnt/

simple-cdd specific part:

  1. Run build-simple-cdd as usual
  2. Copy the ISO file generated by build-simple-cdd in the USB key. Any name will do, as long as it ends in .iso the installer will find it
  3. Configure the boot loader, fetching the kernel command line out of the cdrom boot loader generated by simple-cdd:
    • echo default vmlinuz > /mnt/syslinux.cfg
    • grep append tmp/cd-build/etch/boot1/isolinux/isolinux.cfg | head -1 | sed -e 's/^\t//' -e 's/ initrd=[^ ]*/ initrd=initrd.gz/' >> /mnt/syslinux.cfg

This is it, it works nicely, perfectly scriptable, tested today.