uboot/doc/README.plan9
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   1Plan 9 from Bell Labs kernel images require additional setup to pass
   2configuration information to the kernel.  An environment variable named
   3confaddr must be defined with the same value as CONFADDR (see mem.h).
   4Use of this facility is optional, but should be preferable to manual
   5configuration.
   6
   7When booting an image, arguments supplied to the bootm command will be
   8copied to CONFADDR.  If no arguments are specified, the contents of the
   9bootargs environment variable will be copied.
  10
  11If no command line arguments or bootargs are defined, CONFADDR is left
  12uninitialized to permit manual configuration.  For example, PC-style
  13configuration could be simulated by issuing a fatload in bootcmd:
  14
  15  # setenv bootcmd fatload mmc 0 $confaddr plan9.ini; ...; bootm
  16
  17Steven Stallion
  18June 2013
  19