diff --git a/src/uxn.c b/src/uxn.c
index 6aaa73a..870a361 100644
--- a/src/uxn.c
+++ b/src/uxn.c
@@ -96,7 +96,7 @@ err:
 /* clang-format on */
 
 int
-uxn_boot(Uxn *u, Uint8 *ram)
+uxn_boot(Uxn *u, Uint8 *ram, Uint8 (*dei)(struct Uxn *, Uint8), void (*deo)(struct Uxn *, Uint8, Uint8))
 {
 	Uint32 i;
 	char *cptr = (char *)u;
@@ -106,5 +106,7 @@ uxn_boot(Uxn *u, Uint8 *ram)
 	u->wst = (Stack *)(ram + 0x10000);
 	u->rst = (Stack *)(ram + 0x10100);
 	u->dev = (Uint8 *)(ram + 0x10200);
+	u->dei = dei;
+	u->deo = deo;
 	return 1;
 }
diff --git a/src/uxn.h b/src/uxn.h
index 58339af..83aec2b 100644
--- a/src/uxn.h
+++ b/src/uxn.h
@@ -36,6 +36,6 @@ typedef struct Uxn {
 	void (*deo)(struct Uxn *u, Uint8 addr, Uint8 value);
 } Uxn;
 
-int uxn_boot(Uxn *u, Uint8 *ram);
+int uxn_boot(Uxn *u, Uint8 *ram, Uint8 (*dei)(struct Uxn *, Uint8), void (*deo)(struct Uxn *, Uint8, Uint8));
 int uxn_eval(Uxn *u, Uint16 pc);
 int uxn_halt(Uxn *u, Uint8 instr, Uint8 err, Uint16 addr);
diff --git a/src/uxn11.c b/src/uxn11.c
index 5475149..7c30b0b 100644
--- a/src/uxn11.c
+++ b/src/uxn11.c
@@ -227,10 +227,8 @@ main(int argc, char **argv)
 	if(argc < 2)
 		return emu_error("Usage", "uxn11 game.rom args");
 	rom_path = argv[1];
-	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8))))
+	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8)), emu_dei, emu_deo))
 		return emu_error("Boot", "Failed");
-	u.dei = emu_dei;
-	u.deo = emu_deo;
 	/* start sequence */
 	if(!emu_start(&u, rom_path))
 		return emu_error("Start", rom_path);
diff --git a/src/uxncli.c b/src/uxncli.c
index bb98e6e..66f0683 100644
--- a/src/uxncli.c
+++ b/src/uxncli.c
@@ -75,10 +75,8 @@ main(int argc, char **argv)
 	int i;
 	if(argc < 2)
 		return emu_error("Usage", "uxncli game.rom args");
-	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8))))
+	if(!uxn_boot(&u, (Uint8 *)calloc(0x10300, sizeof(Uint8)), emu_dei, emu_deo))
 		return emu_error("Boot", "Failed");
-	u.dei = emu_dei;
-	u.deo = emu_deo;
 	if(!load_rom(&u, argv[1]))
 		return emu_error("Load", "Failed");
 	fprintf(stderr, "Loaded %s\n", argv[1]);