diff --git a/Makefile b/Makefile
index 7774a5f..974f828 100644
--- a/Makefile
+++ b/Makefile
@@ -74,6 +74,11 @@ scsp/sine-44100-s16be-1ch.pcm:
 
 scsp/slot.elf: scsp/slot.o scsp/sine-44100-s16be-1ch.pcm.o
 
+m68k:
+
+m68k/%.bin: m68k
+	$(MAKE) -C m68k $(notdir $@)
+
 scsp/sound_cpu.elf: scsp/sound_cpu.o m68k/slot.bin.o
 
 # clean
@@ -89,3 +94,6 @@ clean-sh:
 		common/keyboard.cpp \
 		common/keyboard.hpp \
 		wordle/word_list.hpp
+
+
+PHONY: m68k
diff --git a/m68k/main.cpp b/m68k/main.cpp
deleted file mode 100644
index a73c095..0000000
--- a/m68k/main.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-extern "C"
-void start(void)
-{
-  while (1) {}
-}
diff --git a/m68k/slot.cpp b/m68k/slot.cpp
index 353a739..28b405c 100644
--- a/m68k/slot.cpp
+++ b/m68k/slot.cpp
@@ -10,7 +10,7 @@ void main()
 {
   for (long i = 0; i < 807; i++) { asm volatile ("nop"); }   // wait for (way) more than 30µs
 
-  scsp.reg.ctrl.MIXER = MIXER__MEM4MB | MIXER__DAC18B | MIXER__MVOL(0xf);
+  scsp.reg.ctrl.MIXER = MIXER__MEM4MB | MIXER__MVOL(0xf);
 
   const uint32_t sine_start = reinterpret_cast<uint32_t>(&_sine_start);
 
diff --git a/scsp/sound_cpu.cpp b/scsp/sound_cpu.cpp
index c5128f9..1edd683 100644
--- a/scsp/sound_cpu.cpp
+++ b/scsp/sound_cpu.cpp
@@ -2,45 +2,35 @@
 
 #include "smpc.h"
 #include "scsp.h"
-#include "vdp2.h"
 
 #include "../common/copy.hpp"
-#include "../common/vdp2_func.hpp"
 
 extern void * _binary_m68k_slot_bin_start __asm("_binary_m68k_slot_bin_start");
 extern void * _binary_m68k_slot_bin_size __asm("_binary_m68k_slot_bin_size");
 
 void main()
 {
-  v_blank_in();
+  /* SEGA SATURN TECHNICAL BULLETIN # 51
 
-  /*
-  while ((smpc.reg.SF & 1) != 0);
-  smpc.reg.SF = 1;
-  smpc.reg.COMREG = COMREG__SNDOFF;
-  while (smpc.reg.oreg[31] != 0b00000111);
+     The document suggests that Sound RAM is (somewhat) preserved
+     during SNDOFF.
+   */
   
   while ((smpc.reg.SF & 1) != 0);
   smpc.reg.SF = 1;
-  smpc.reg.COMREG = COMREG__SNDON;
-  while (smpc.reg.oreg[31] != 0b00000110);
-  */
+  smpc.reg.COMREG = COMREG__SNDOFF;
+  while (smpc.reg.oreg[31] != OREG31__SNDOFF);
 
-  scsp.reg.ctrl.MIXER = MIXER__MEM4MB | MIXER__DAC18B | MIXER__MVOL(0xf);
+  scsp.reg.ctrl.MIXER = MIXER__MEM4MB;
   
   uint32_t * m68k_main_start = (uint32_t *)&_binary_m68k_slot_bin_start;
   uint32_t m68k_main_size = (uint32_t)&_binary_m68k_slot_bin_size;
   copy<uint32_t>(&scsp.ram.u32[0], m68k_main_start, m68k_main_size);
-    
-  while ((smpc.reg.SF & 1) != 0);
-  smpc.reg.SF = 1;
-  smpc.reg.COMREG = COMREG__SNDOFF;
-  while (smpc.reg.oreg[31] != 0b00000111);
   
   while ((smpc.reg.SF & 1) != 0);
   smpc.reg.SF = 1;
   smpc.reg.COMREG = COMREG__SNDON;
-  while (smpc.reg.oreg[31] != 0b00000110);
+  while (smpc.reg.oreg[31] != OREG31__SNDON);
   
   // do nothing while the sound CPU manipulates the SCSP
 }