diff --git a/include/image.mk b/include/image.mk
index 8755c4832a..8592c19b99 100644
--- a/include/image.mk
+++ b/include/image.mk
@@ -30,7 +30,7 @@ param_get_default = $(firstword $(call param_get,$(1),$(2)) $(3))
 param_mangle = $(subst $(space),_,$(strip $(1)))
 param_unmangle = $(subst _,$(space),$(1))
 
-mkfs_packages_id = $(shell echo $(sort $(1)) | mkhash md5 | head -c 8)
+mkfs_packages_id = $(shell echo $(sort $(1)) | mkhash md5 | cut -b1-8)
 mkfs_target_dir = $(if $(call param_get,pkg,$(1)),$(KDIR)/target-dir-$(call param_get,pkg,$(1)),$(TARGET_DIR))
 
 KDIR=$(KERNEL_BUILD_DIR)
@@ -44,7 +44,7 @@ IMG_PREFIX_VERCODE:=$(if $(CONFIG_VERSION_CODE_FILENAMES),$(call sanitize,$(VERS
 IMG_PREFIX:=$(VERSION_DIST_SANITIZED)-$(IMG_PREFIX_VERNUM)$(IMG_PREFIX_VERCODE)$(IMG_PREFIX_EXTRA)$(BOARD)$(if $(SUBTARGET),-$(SUBTARGET))
 IMG_ROOTFS:=$(IMG_PREFIX)-rootfs
 IMG_COMBINED:=$(IMG_PREFIX)-combined
-IMG_PART_SIGNATURE:=$(shell echo $(SOURCE_DATE_EPOCH)$(LINUX_VERMAGIC) | mkhash md5 | head --bytes 8)
+IMG_PART_SIGNATURE:=$(shell echo $(SOURCE_DATE_EPOCH)$(LINUX_VERMAGIC) | mkhash md5 | cut -b1-8)
 
 MKFS_DEVTABLE_OPT := -D $(INCLUDE_DIR)/device_table.txt