diff --git a/classes/image_types_phosphor.bbclass b/classes/image_types_phosphor.bbclass
index 3980120..e466347 100644
--- a/classes/image_types_phosphor.bbclass
+++ b/classes/image_types_phosphor.bbclass
@@ -55,6 +55,7 @@
 FLASH_UBI_RWFS_TXT_SIZE_flash-131072 ?= "32MiB"
 
 # eMMC sizes in KB unless otherwise noted.
+MMC_UBOOT_SIZE ?= "1024"
 MMC_BOOT_PARTITION_SIZE ?= "65536"
 
 SIGNING_KEY ?= "${STAGING_DIR_NATIVE}${datadir}/OpenBMC.priv"
@@ -104,6 +105,12 @@
 		| tr '\000' '\377' > $image_dst
 }
 
+mk_empty_image_zeros() {
+	image_dst="$1"
+	image_size_kb=$2
+	dd if=/dev/zero of=$image_dst bs=1k count=$image_size_kb
+}
+
 clean_rwfs() {
 	type=$1
 	shift
@@ -423,13 +430,14 @@
 
 do_generate_ext4_tar() {
 	# Generate the U-Boot image
+	mk_empty_image_zeros image-u-boot ${MMC_UBOOT_SIZE}
 	do_generate_image_uboot_file image-u-boot
 
 	# Generate a compressed ext4 filesystem with the fitImage file in it to be
 	# flashed to the boot partition of the eMMC
 	install -d boot-image
 	install -m 644 ${DEPLOY_DIR_IMAGE}/${FLASH_KERNEL_IMAGE} boot-image/fitImage
-	mk_empty_image boot-image.${FLASH_EXT4_BASETYPE} ${MMC_BOOT_PARTITION_SIZE}
+	mk_empty_image_zeros boot-image.${FLASH_EXT4_BASETYPE} ${MMC_BOOT_PARTITION_SIZE}
 	mkfs.ext4 -F -i 4096 -d boot-image boot-image.${FLASH_EXT4_BASETYPE}
 	# Error codes 0-3 indicate successfull operation of fsck
 	fsck.ext4 -pvfD boot-image.${FLASH_EXT4_BASETYPE} || [ $? -le 3 ]