diff --git a/Makefile.inc1 b/Makefile.inc1
index fd27aea6fdee..77ca2dccb2df 100644
--- a/Makefile.inc1
+++ b/Makefile.inc1
@@ -1559,12 +1559,6 @@ INSTALLKERNEL= ${_kernel}
 .endfor
 
 _cleankernobj_fast_depend_hack: .PHONY
-# 20180320 remove stale generated assym.s after renaming to .inc in r331254
-	@if [ -e "${OBJTOP}/sys/${KERNCONF}/assym.s" ]; then \
-		echo "Removing stale generated assym files"; \
-		rm -f ${OBJTOP}/sys/${KERNCONF}/assym.* \
-		    ${OBJTOP}/sys/${KERNCONF}/.depend.assym.*; \
-	fi
 # 20191009  r353340  removal of opensolaris_atomic.S (also r353381)
 .if ${MACHINE} != i386
 .for f in opensolaris_atomic