A common message from RedBoot is:
  FLASH configuration checksum error or invalid key

This is not really an error, but just a warning.  RedBoot can keep
configuration information in FLASH (or EEPROM).  This is a database
which must be initialized before use.  The warning simply means
that somehow the database is not valid, probably because it has
never been initialized.

To remedy this, simply initialize the database!  For example:
  RedBoot> fconfig -i
  Initialize non-volatile configuration - continue (y/n)? y
  Run script at boot: false
  Use BOOTP for network configuration: true
  DNS server IP address: 
  Network hardware address [MAC]: 0x00:0x23:0x31:0x37:0x00:0x1C
  GDB connection port: 9000
  Force console for special debug messages: false
  Network debug at boot time: false
  Default network device: at91rm9200_eth
  Update RedBoot non-volatile configuration - continue (y/n)? y