IORegistryEntry::fromPath() fail

my IOKit kext is failing on older iMacs to locate the /options path in the DeviceTree plane of the IORegistry. has anybody else encountered this or know why it would fail? thx->adv

  IORegistryEntry* regEntry = IORegistryEntry::fromPath("/options", gIODTPlane);
  if(NULL == regEntry)
  {
    regEntry = IORegistryEntry::fromPath("IODeviceTree:/options");  
    if(NULL == regEntry)
    {
      DEBUG_LOG("getIORegOptionsEntry: FAILURE TO LOCATE: IODe开发者_JAVA百科viceTree:/options\n");
    }
  }

The path used to create IORegistryEntry is invalid as per the API: it should begins with a ':'. The I/O plane should not be included in the path, but as the second parameter.