--- src/VBox/Devices/PC/ipxe/Makefile.kmk.orig	2021-01-07 15:39:44 UTC
+++ src/VBox/Devices/PC/ipxe/Makefile.kmk
@@ -121,7 +121,7 @@ endif
 	-falign-loops=1 \
 	-Os \
 	-falign-functions=1 \
-	-mpreferred-stack-boundary=2 \
+	-mstack-alignment=2 \
 	-mregparm=3 \
 	-mrtd \
 	-freg-struct-return \
@@ -144,7 +144,7 @@ endif
 	-falign-jumps=1 \
 	-falign-loops=1 \
 	-falign-functions=1 \
-	-mpreferred-stack-boundary=2 \
+	-mstack-alignment=2 \
 	-mregparm=3 \
 	-mrtd \
 	-freg-struct-return \