Cisco Systems ROMMON, Version 1.1.15, RELEASE SOFTWARE
Copyright (c) 1994-2019 by Cisco Systems, Inc.
Compiled Sat 03/30/2019 7:00:46.51 by wchen64
Current image running: Boot ROM0
Last reset cause: PowerOn
DIMM Slot 0 : Present
DIMM Slot 1 : Present
Platform ASA5508 with 8192 Mbytes of main memory
MAC Address: 00:5d:73:50:33:d7
Use BREAK or ESC to interrupt boot.
Use SPACE to begin boot immediately.
File system not supported
Attempt autoboot: "boot disk0:"
File system not supported
boot: cannot determine first file name on device "disk0:"
autoboot: All boot attempts have failed.
autoboot: Restarting the system.
Why are ASA FirePower 5508x reporting file system not supported on device "disk0" ? It is very strange how can people to solving it.