The default network configuration is:

See Crypto Hardware Acceleration

Connect device to Ethernet port. To prevent automatic updates by cloud engines (which may disable ssh access), use a separate switch or disconnect your router from the internet. If the ssh access was disabled by the automatic cloud engine update service, you need to login there and re-activate ssh.

Find IP address, BE and EF are the last two bytes of the MAC of your device (printed on the bottom of the GoFlexHome)

root@host ~ # ifconfig eth0 169.254.1.0 
root@host ~ # nmap -e eth0 -sP $(printf "169.254.%d.%d" 0xbe 0xef)

Connect to IP address via ssh (root / stxadmin) to see if it works.

If you want to restore the original firmware at a later point use this guide to make a backup. You need to login to the original firmware via ssh first. Another method beside using "dd" is nanddump. To be on the safe side, you should take a 2nd backup with the nanddump method. Assuming you have a USB Stick or other USB drive mapped via sda - you can try this:

cd /tmp
mkdir backup
mount /dev/sda1 /tmp/backup
wget http://plugapps.com/os/pogoplug/uboot/nanddump
chmod +x nanddump
./nanddump -nf backup/mtd0 /dev/mtd0
./nanddump -nf backup/mtd1 /dev/mtd1
./nanddump -nf backup/mtd2 /dev/mtd2
umount /dev/sda1