Package: initramfs-tools-core Version: 0.121 If I try to run update-initramfs while busybox is not installed, I get an error message: E: busybox is required but not installed E: /usr/share/initramfs-tools/hooks/busybox failed with return 1. This happens irrespective of the BUSYBOX setting in /etc/initramfs-tools/initramfs.conf.