Same problem on Ubuntu 14.04.4 during a VM install on /dev/sda1 which is a /boot partition from previous install get automounted even with folllowing commands in the kickstart.
preseed partman/umount_active boolean true preseed preseed/early_command string umount /media || true
Same problem on Ubuntu 14.04.4 during a VM install on /dev/sda1 which is a /boot partition from previous install get automounted even with folllowing commands in the kickstart.
preseed partman/ umount_ active boolean true early_command string umount /media || true
preseed preseed/