diff --git a/package/skeleton-custom/skeleton-custom.mk b/package/skeleton-custom/skeleton-custom.mk
index 4aebe3f3b1..b514f8017b 100644
--- a/package/skeleton-custom/skeleton-custom.mk
+++ b/package/skeleton-custom/skeleton-custom.mk
@@ -20,11 +20,8 @@ ifeq ($(BR2_PACKAGE_SKELETON_CUSTOM)$(BR_BUILDING),yy)
 ifeq ($(SKELETON_CUSTOM_PATH),)
 $(error No path specified for the custom skeleton)
 endif
+endif
 
-ifeq ($(BR2_ROOTFS_MERGED_USR),y)
-
-# Ensure the user has prepared a merged /usr.
-#
 # Extract the inode numbers for all of those directories. In case any is
 # a symlink, we want to get the inode of the pointed-to directory, so we
 # append '/.' to be sure we get the target directory. Since the symlinks
@@ -38,6 +35,10 @@ SKELETON_CUSTOM_USR_LIB_INODE = $(shell stat -c '%i' $(SKELETON_CUSTOM_PATH)/usr
 SKELETON_CUSTOM_USR_BIN_INODE = $(shell stat -c '%i' $(SKELETON_CUSTOM_PATH)/usr/bin/.)
 SKELETON_CUSTOM_USR_SBIN_INODE = $(shell stat -c '%i' $(SKELETON_CUSTOM_PATH)/usr/sbin/.)
 
+# For a merged /usr, ensure that /lib, /bin and /sbin and their /usr
+# counterparts are appropriately setup as symlinks ones to the others.
+ifeq ($(BR2_ROOTFS_MERGED_USR),y)
+
 ifneq ($(SKELETON_CUSTOM_LIB_INODE),$(SKELETON_CUSTOM_USR_LIB_INODE))
 SKELETON_CUSTOM_NOT_MERGED_USR += /lib
 endif
@@ -48,14 +49,15 @@ ifneq ($(SKELETON_CUSTOM_SBIN_INODE),$(SKELETON_CUSTOM_USR_SBIN_INODE))
 SKELETON_CUSTOM_NOT_MERGED_USR += /sbin
 endif
 
+endif # merged /usr
+
+ifeq ($(BR2_PACKAGE_SKELETON_CUSTOM)$(BR_BUILDING),yy)
 ifneq ($(SKELETON_CUSTOM_NOT_MERGED_USR),)
 $(error The custom skeleton in $(SKELETON_CUSTOM_PATH) is not \
 	using a merged /usr for the following directories: \
 	$(SKELETON_CUSTOM_NOT_MERGED_USR))
 endif
-
-endif # merged /usr
-endif # ! building
+endif
 
 define SKELETON_CUSTOM_INSTALL_TARGET_CMDS
 	$(call SYSTEM_RSYNC,$(SKELETON_CUSTOM_PATH),$(TARGET_DIR))