diff --git a/meta-arm-bsp/conf/machine/fvp-base-arm32.conf b/meta-arm-bsp/conf/machine/fvp-base-arm32.conf
index 3c3e5acf..36beca1d 100644
--- a/meta-arm-bsp/conf/machine/fvp-base-arm32.conf
+++ b/meta-arm-bsp/conf/machine/fvp-base-arm32.conf
@@ -9,7 +9,7 @@ require conf/machine/include/arm/arch-armv7a.inc
 
 KERNEL_IMAGETYPE = "zImage"
 
-PREFERRED_VERSION_trusted-firmware-a ?= "2.2%"
+PREFERRED_VERSION_trusted-firmware-a = "2.2%"
 
 # FVP u-boot configuration
 UBOOT_MACHINE = "vexpress_aemv8a_aarch32_defconfig"