diff --git a/meta-arm-bsp/conf/machine/sbsa-ref.conf b/meta-arm-bsp/conf/machine/sbsa-ref.conf
index eefbb2e9cac2..d05e44677e0d 100644
--- a/meta-arm-bsp/conf/machine/sbsa-ref.conf
+++ b/meta-arm-bsp/conf/machine/sbsa-ref.conf
@@ -44,7 +44,7 @@ QB_NETWORK_DEVICE = "-device e1000e,netdev=net0,mac=@MAC@"
 QB_DRIVE_TYPE = "/dev/hd"
 QB_ROOTFS_OPT = "-drive file=@ROOTFS@,if=ide,format=qcow2"
 QB_DEFAULT_KERNEL = "none"
-QB_OPT_APPEND = "-device usb-tablet -device usb-kbd -drive if=pflash,format=raw,unit=0,readonly,file=@DEPLOY_DIR_IMAGE@/SBSA_FLASH0.fd -drive if=pflash,format=raw,unit=1,readonly,file=@DEPLOY_DIR_IMAGE@/SBSA_FLASH1.fd"
+QB_OPT_APPEND = "-device usb-tablet -device usb-kbd -drive if=pflash,format=raw,unit=0,readonly=on,file=@DEPLOY_DIR_IMAGE@/SBSA_FLASH0.fd -drive if=pflash,format=raw,unit=1,readonly=on,file=@DEPLOY_DIR_IMAGE@/SBSA_FLASH1.fd"
 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 -device virtconsole,chardev=virtcon"
 # sbsa-ref is a true virtual machine so can't use KVM