I don't quite understand your question.
Flexbuild can separately build each component, or it can automatically build all the components; it generates the composite firmware(containing RCW, U-Boot/UEFI, PHY firmware, kernel image, dtb, initrd) and NXP LSDK userland (containing the specified
packages and application components).
Look at section 5.4.4.3 LS1046ARDB of the Layerscape Software Development Kit User Guide, Rev. 20.04, 04/2020 document.
