The overall approach is to: - download and write a stock raspian image to an sd card - tweak the init script at /usr/share/initramfs-tools/init to create the

The overall approach is to: - download and write a stock raspian image to an sd card - tweak the init script at /usr/share/initramfs-tools/init to create the ramdisk file system and to insert the download path + download + write part - use mkinitramfs to create the image (read the man for mkinitramfs) - replace the initramfs img in the SD boot partition with the one you've just built - tweak the cmdline.txt and the config.txt files for the boot partition to use the new initrd - pack the boot partition image.