Illegal option: --
Usage: acpidump [options]
Options:
  -b                  Dump tables to binary files
  -h -?               This help message
  -o <File>           Redirect output to file
  -r <Address>        Dump tables from specified RSDP
  -s                  Print table summaries only
  -v                  Display version information
  -vd                 Display build date and time
  -z                  Verbose mode

Table Options:
  -a <Address>        Get table via a physical address
  -c <on|off>         Turning on/off customized table dumping
  -f <BinaryFile>     Get table via a binary file
  -n <Signature>      Get table via a name/signature
  -x                  Use RSDT instead of XSDT

Invocation without parameters dumps all available tables
Multiple mixed instances of -a, -f, and -n are supported