Set-up a Raspbian hard drive image for Raspberry Pi using SD card.

Download the latest Raspbian Image

The quick and easy method is to put the image on BOTH the SD card and the HDD, boot up the Pi on the SD card and from there, connect and prepare the HDD to boot to.

Since the HDD image is a duplicate, the partition’s uuid should be changed so that it is unique, at the same time the partitions label can be set. The harddisk’s filesystem must then be mounted in order to access it, so create a directory called hdd in the existing media directory and then mount the new hdd image to that directory.

sudo tune2fs -U random -L hdd  /dev/sda2
sudo mkdir /media/hdd
sudo mount /dev/sda2 /media/hdd
sudo nano /media/hdd/etc/fstab

This last line opens the hdd’s fstab for editing, change the default root location from “ /dev/mmcblk0p2 “ to “ /dev/sda2 “ then save and exit using ctrl-X -> Y -> enter,

Next edit the cmdline.txt to point to the HDD at boot time.

sudo sh -c 'echo "dwc_otg.lpm_enable=0 console=tty1 root=/dev/sda2 rootfstype=ext4 elevator=deadline rootwait" > /boot/cmdline.txt'

note - this command also removes text from cmdline.txt that effects the serial UART , check before re-starting Pi

sudo shutdown -r now

The Pi should now boot up to the HDD, now is a good time to perform an update and upgrade the Raspbian image.

sudo apt-get update
sudo apt-get upgrade -y

The downloaded image’s root partition is quite small and as a result it maybe necessary to re-size HDD .

Since the new installation was created from 2 identical images and uses the boot partition of the SD card to boot to the hdd’s main partition, the small “boot” partition on the hdd can be ignored as it is only 56MB.

The second or main partition of your sdcard also holds a redundant copy of raspbian, this can be quite useful as if you have an issue with your “hdd” partition and are unable to boot or access it, you can whip the sdcard out and on windows PC using notepad, edit the /boot/cmdline.txt file by changing “/dev/sda2” to “/sda/mmcblk0p2”, pop it back into the pi, boot onto the sdcard and explore / fix your broken “hdd” image.

There are tidier methods to do this but this is by far the easiest and most reliable way without another linux machine.