newer Kernel caused Error: "BusyBox v1.36.1 (Ubuntu 1:1.36.1-6ubuntu3.1) built-in shell (ash)"

Out of nowhere came this error. The system is not firing up anymore. See below boot messages. Please help (I have files that are not in backup yet...) BusyBox v1.36.1 (Ubuntu 1:1.36.1-6ubuntu3.1) b...