BBGG first steps...

Machine: [SeeedStudio_BeagleBone_Green_Gateway]
/usr/sbin/update-initramfs: option requires an argument -- 'k'

Usage: update-initramfs {-c|-d|-u} [-k version] [-v] [-b directory]

Options:
 -k version     Specify kernel version or 'all'
 -c             Create a new initramfs
 -u             Update an existing initramfs
 -d             Remove an existing initramfs
 -b directory   Set alternate boot directory
 -v             Be verbose

See update-initramfs(8) for further details.