diff --git a/arch/sandbox/Makefile b/arch/sandbox/Makefile
index 2610794..f6cf859 100644
--- a/arch/sandbox/Makefile
+++ b/arch/sandbox/Makefile
@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0+
 
-head-y := arch/sandbox/cpu/start.o
-
+head-y := arch/sandbox/cpu/start.o arch/sandbox/cpu/os.o
+head-$(CONFIG_SANDBOX_SDL) += arch/sandbox/cpu/sdl.o
 libs-y += arch/sandbox/cpu/
 libs-y += arch/sandbox/lib/