anchor.diff:  python () {
       baseaddr = d.getVar('DDR_BASEADDR') or "0x0"
       if baseaddr == "0x0":
  -        d.setVar('PRE_BOOTENV','')
  +        d.appendVar('PRE_BOOTENV','')
       else:
           soc_family = d.getVar('SOC_FAMILY') or ""
           if soc_family == "zynqmp":
  
positive.code: 
  DDR_BASEADDR ?= "0x0"
  DDR_BASEADDR_microblaze ?= "0x80000000"
  
  SRC_URI = " \
              file://boot.cmd.sd.zynq \
  
negative.code: 
  NAND_KERNEL_IMAGE ?= "image.ub"
  
  QSPI_FIT_IMAGE_LOAD_ADDRESS ?= "${@append_baseaddr(d,d.getVar('QSPI_FIT_IMAGE_OFFSET'))}"
  QSPI_FIT_IMAGE_OFFSET ?= "0x10000000"
  QSPI_FIT_IMAGE_SIZE ?= "0x6400000"
  QSPI_FIT_IMAGE_SIZE_zynqmpdr ?= "0x3F00000"
  QSPI_FIT_IMAGE_SIZE_zynq ?= "0xF00000"
  QSPI_FIT_IMAGE_SIZE_microblaze ?= "0xF00000"
  
  NAND_FIT_IMAGE_LOAD_ADDRESS ?= "${@append_baseaddr(d,d.getVar('NAND_FIT_IMAGE_OFFSET'))}"
  NAND_FIT_IMAGE_OFFSET ?= "0x10000000"
  NAND_FIT_IMAGE_SIZE ?= "0x6400000"
  
  SDBOOTDEV ?= "0"
  