diff --git a/wic/imx-imx-boot-bootpart.wks.in b/wic/imx-imx-boot-bootpart.wks.in
index e8e6e891..46a2a0a6 100644
--- a/wic/imx-imx-boot-bootpart.wks.in
+++ b/wic/imx-imx-boot-bootpart.wks.in
@@ -14,7 +14,7 @@
 #   ${IMX_BOOT_SEEK} 32 or 33kiB, see reference manual
 #
 part u-boot --source rawcopy --sourceparams="file=imx-boot.tagged" --ondisk mmcblk --no-table --align ${IMX_BOOT_SEEK}
-part /boot --source bootimg-partition --ondisk mmcblk --fstype=vfat --label boot --active --align 8192 --size 256
+part /boot --source bootimg-partition --ondisk mmcblk --fstype=vfat --label boot --active --align 8192 --fixed-size 256
 part / --source rootfs --ondisk mmcblk --fstype=ext4 --label root --align 8192
 
 bootloader --ptable msdos