diff --git a/meta-yocto-bsp/conf/machine/genericarm64.conf b/meta-yocto-bsp/conf/machine/genericarm64.conf
index b6dfb8042d3..f5000402e51 100644
--- a/meta-yocto-bsp/conf/machine/genericarm64.conf
+++ b/meta-yocto-bsp/conf/machine/genericarm64.conf
@@ -33,31 +33,31 @@ SERIAL_CONSOLES ?= "115200;ttyAMA0 115200;hvc0 115200;ttyS0 115200;ttyS1 115200;
 # Allow u-boot to be built for use with qemu-system-aarch64.
 # This u-boot is _not_ suitable for use with real hardware, and the expectation
 # of this machine is that real hardware comes with the firmware pre-loaded.
-UBOOT_MACHINE = "qemu_arm64_defconfig"
+UBOOT_MACHINE ?= "qemu_arm64_defconfig"
 
 # runqemu configuration to run a genericarm64 image inside a qemu-system-aarch64. You will need
 # to build u-boot explicitly.
 IMAGE_CLASSES += "qemuboot"
-QB_SYSTEM_NAME = "qemu-system-aarch64"
+QB_SYSTEM_NAME ?= "qemu-system-aarch64"
 # Boot the virtual machine with either an emulated Cortex-A76, or the host if using KVM
-QB_MACHINE = "-machine virt"
-QB_CPU = "-cpu cortex-a76"
-QB_CPU_KVM = "-cpu host -machine gic-version=3"
-QB_SMP = "-smp 4"
+QB_MACHINE ?= "-machine virt"
+QB_CPU ?= "-cpu cortex-a76"
+QB_CPU_KVM ?= "-cpu host -machine gic-version=3"
+QB_SMP ?= "-smp 4"
 # Boot into U-Boot and let that scan the disk for the next step, don't pass any kernel or filesystem hints
-QB_DEFAULT_BIOS = "u-boot.bin"
-QB_DEFAULT_KERNEL = "none"
-QB_DEFAULT_FSTYPE = "wic"
-QB_FSINFO = "wic:no-kernel-in-fs"
+QB_DEFAULT_BIOS ?= "u-boot.bin"
+QB_DEFAULT_KERNEL ?= "none"
+QB_DEFAULT_FSTYPE ?= "wic"
+QB_FSINFO ?= "wic:no-kernel-in-fs"
 # Mount the wic rootfs as a virtio block device
-QB_ROOTFS_OPT = "-drive id=root,file=@ROOTFS@,if=none,format=raw -device virtio-blk-pci,drive=root"
+QB_ROOTFS_OPT ?= "-drive id=root,file=@ROOTFS@,if=none,format=raw -device virtio-blk-pci,drive=root"
 # Virtio graphics
-QB_GRAPHICS = "-device virtio-gpu-pci"
+QB_GRAPHICS ?= "-device virtio-gpu-pci"
 # Virtio serial consoles
-QB_SERIAL_OPT = "-device virtio-serial-pci -chardev null,id=virtcon -device virtconsole,chardev=virtcon"
-QB_TCPSERIAL_OPT = "-device virtio-serial-pci -chardev socket,id=virtcon,port=@PORT@,host=127.0.0.1,nodelay=on -device virtconsole,chardev=virtcon"
+QB_SERIAL_OPT ?= "-device virtio-serial-pci -chardev null,id=virtcon -device virtconsole,chardev=virtcon"
+QB_TCPSERIAL_OPT ?= "-device virtio-serial-pci -chardev socket,id=virtcon,port=@PORT@,host=127.0.0.1,nodelay=on -device virtconsole,chardev=virtcon"
 # Virtio networking
-QB_TAP_OPT = "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no"
+QB_TAP_OPT ?= "-netdev tap,id=net0,ifname=@TAP@,script=no,downscript=no"
 
 # If we're running testimage then we're in a qemu, so ensure u-boot is build
 TESTIMAGEDEPENDS:append = " u-boot:do_deploy"