diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 72f4b0899..ea48355ad 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -632,6 +632,11 @@ void DivEngine::renderSamples() {
   }
 }
 
+DivInstrument* DivEngine::getIns(int index) {
+  if (index<0 || index>=song.insLen) return &song.nullIns;
+  return song.ins[index];
+}
+
 void DivEngine::play() {
   
 }
diff --git a/src/engine/engine.h b/src/engine/engine.h
index d31653603..595b26d34 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -62,6 +62,7 @@ class DivEngine {
   public:
     DivSong song;
     void nextBuf(float** in, float** out, int inChans, int outChans, unsigned int size);
+    DivInstrument* getIns(int index);
     // load a .dmf.
     bool load(void* f, size_t length);
     // save as .dmf.
diff --git a/src/engine/instrument.h b/src/engine/instrument.h
index fd0c1b403..6372a5d06 100644
--- a/src/engine/instrument.h
+++ b/src/engine/instrument.h
@@ -49,5 +49,14 @@ struct DivInstrument {
   DivInstrumentSTD std;
   DivInstrumentGB gb;
   DivInstrumentC64 c64;
+  DivInstrument():
+    name(""),
+    mode(false),
+    type(DIV_INS_FM) {
+    memset(&fm,0,sizeof(DivInstrumentFM));
+    memset(&std,0,sizeof(DivInstrumentSTD));
+    memset(&gb,0,sizeof(DivInstrumentGB));
+    memset(&c64,0,sizeof(DivInstrumentC64));
+  }
 };
 #endif
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index d959cd707..bb14755e0 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -10,7 +10,7 @@ void DivPlatformGenesis::acquire(int& l, int& r) {
     if (--dacPeriod<1) {
       DivSample* s=parent->song.sample[dacSample];
       writes.emplace(0x2a,((unsigned short)s->rendData[dacPos++]+0x8000)>>8);
-      if (dacPos>s->rendLength) {
+      if (dacPos>=s->rendLength) {
         dacSample=-1;
       }
       dacPeriod=dacRate;
@@ -95,6 +95,7 @@ void DivPlatformGenesis::tick() {
 
   for (int i=0; i<6; i++) {
     if (chan[i].freqChanged) {
+      chan[i].freq=(chan[i].baseFreq*(ONE_SEMITONE+chan[i].pitch))/ONE_SEMITONE;
       if (chan[i].freq>=82432) {
         chan[i].freqH=((chan[i].freq>>15)&7)|0x38;
         chan[i].freqL=(chan[i].freq>>7)&0xff;
@@ -152,7 +153,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
         dacRate=dacRates[parent->song.sample[dacSample]->rate];
         break;
       }
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       
       for (int i=0; i<4; i++) {
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];
@@ -172,7 +173,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       rWrite(chanOffs[c.chan]+0xb0,(ins->fm.alg&7)|(ins->fm.fb<<3));
       rWrite(chanOffs[c.chan]+0xb4,(chan[c.chan].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
       chan[c.chan].baseFreq=644.0f*pow(2.0f,((float)c.value/12.0f));
-      chan[c.chan].freq=(chan[c.chan].baseFreq*(ONE_SEMITONE+chan[c.chan].pitch))/ONE_SEMITONE;
+      
       chan[c.chan].freqChanged=true;
       chan[c.chan].keyOn=true;
       chan[c.chan].active=true;
@@ -184,7 +185,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       break;
     case DIV_CMD_VOLUME: {
       chan[c.chan].vol=c.value;
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       for (int i=0; i<4; i++) {
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];
         DivInstrumentFM::Operator op=ins->fm.op[i];
@@ -214,7 +215,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           chan[c.chan].pan=3;
           break;
       }
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       rWrite(chanOffs[c.chan]+0xb4,(chan[c.chan].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
       break;
     }
@@ -260,14 +261,14 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
     }
     case DIV_CMD_FM_MULT: {
       unsigned short baseAddr=chanOffs[c.chan]|opOffs[c.value];
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       DivInstrumentFM::Operator op=ins->fm.op[c.value];
       rWrite(baseAddr+0x30,(c.value2&15)|(dtTable[op.dt&7]<<4));
       break;
     }
     case DIV_CMD_FM_TL: {
       unsigned short baseAddr=chanOffs[c.chan]|opOffs[orderedOps[c.value]];
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (isOutput[ins->fm.alg][c.value]) {
         rWrite(baseAddr+0x40,127-(((127-c.value2)*chan[c.chan].vol)/127));
       } else {
@@ -276,7 +277,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       break;
     }
     case DIV_CMD_FM_AR: {
-      DivInstrument* ins=parent->song.ins[chan[c.chan].ins];
+      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
       if (c.value<0)  {
         for (int i=0; i<4; i++) {
           DivInstrumentFM::Operator op=ins->fm.op[i];
@@ -318,6 +319,8 @@ int DivPlatformGenesis::init(DivEngine* p, int channels, int sugRate) {
   dacRate=0;
   dacSample=-1;
 
+  extMode=false;
+
   // LFO
   writes.emplace(0x22,0x08);
   
diff --git a/src/engine/platform/genesis.h b/src/engine/platform/genesis.h
index 22fd66f5d..e0d5a9f79 100644
--- a/src/engine/platform/genesis.h
+++ b/src/engine/platform/genesis.h
@@ -16,7 +16,7 @@ class DivPlatformGenesis: public DivDispatch {
       bool active, insChanged, freqChanged, keyOn, keyOff;
       signed char vol;
       unsigned char pan;
-      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(0), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(0), pan(3) {}
+      Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(0), pan(3) {}
     };
     Channel chan[10];
     struct QueuedWrite {
@@ -38,6 +38,8 @@ class DivPlatformGenesis: public DivDispatch {
     int dacRate;
     int dacPos;
     int dacSample;
+
+    bool extMode;
   
     short oldWrites[512];
     short pendingWrites[512];
diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index 321267666..88478b35e 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -9,7 +9,6 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
     c.chan-=3;
     return DivPlatformGenesis::dispatch(c);
   }
-  printf("HANDLE: %d %d %d %d\n",c.cmd,c.chan,c.value,c.value2);
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON:
       chan[c.chan].freq=16.4f*pow(2.0f,((float)c.value/12.0f));
@@ -30,3 +29,10 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
 void DivPlatformGenesisExt::tick() {
   DivPlatformGenesis::tick();
 }
+
+int DivPlatformGenesisExt::init(DivEngine* parent, int channels, int sugRate) {
+  DivPlatformGenesis::init(parent,channels,sugRate);
+
+  extMode=true;
+  return 13;
+}
\ No newline at end of file
diff --git a/src/engine/platform/genesisext.h b/src/engine/platform/genesisext.h
index 330fb1ddd..1c67f42eb 100644
--- a/src/engine/platform/genesisext.h
+++ b/src/engine/platform/genesisext.h
@@ -3,7 +3,19 @@
 #include "genesis.h"
 
 class DivPlatformGenesisExt: public DivPlatformGenesis {
+  struct Channel {
+    unsigned char freqH, freqL;
+    int freq, baseFreq, pitch;
+    unsigned char ins;
+    signed char konCycles;
+    bool active, insChanged, freqChanged, keyOn, keyOff;
+    signed char vol;
+    unsigned char pan;
+    Channel(): freqH(0), freqL(0), freq(0), baseFreq(0), pitch(0), ins(-1), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(0), pan(3) {}
+  };
+  Channel opChan[4];
   public:
     int dispatch(DivCommand c);
     void tick();
+    int init(DivEngine* parent, int channels, int sugRate);
 };
diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 5e54c6644..f72729873 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -62,7 +62,7 @@ int DivPlatformSMS::dispatch(DivCommand c) {
       chan[c.chan].note=c.value;
       chan[c.chan].active=true;
       sn->write(0x90|c.chan<<5|(15-chan[c.chan].vol));
-      chan[c.chan].std.init(parent->song.ins[chan[c.chan].ins]);
+      chan[c.chan].std.init(parent->getIns(chan[c.chan].ins));
       break;
     case DIV_CMD_NOTE_OFF:
       chan[c.chan].active=false;
@@ -71,7 +71,7 @@ int DivPlatformSMS::dispatch(DivCommand c) {
       break;
     case DIV_CMD_INSTRUMENT:
       chan[c.chan].ins=c.value;
-      //chan[c.chan].std.init(parent->song.ins[chan[c.chan].ins]);
+      //chan[c.chan].std.init(parent->getIns(chan[c.chan].ins));
       break;
     case DIV_CMD_VOLUME:
       chan[c.chan].vol=c.value;
diff --git a/src/engine/platform/sms.h b/src/engine/platform/sms.h
index 132e4b59b..5a1a6fff6 100644
--- a/src/engine/platform/sms.h
+++ b/src/engine/platform/sms.h
@@ -12,7 +12,7 @@ class DivPlatformSMS: public DivDispatch {
     bool active, insChanged, freqChanged, keyOn, keyOff;
     signed char vol;
     DivMacroInt std;
-    Channel(): freq(0), baseFreq(0), pitch(0), ins(0), note(0), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(15) {}
+    Channel(): freq(0), baseFreq(0), pitch(0), ins(-1), note(0), active(false), insChanged(true), freqChanged(false), keyOn(false), keyOff(false), vol(15) {}
   };
   Channel chan[4];
   unsigned char snNoiseMode;
diff --git a/src/engine/platform/sound/sn76496.cpp b/src/engine/platform/sound/sn76496.cpp
index 5e876c38b..2bce97b1b 100644
--- a/src/engine/platform/sound/sn76496.cpp
+++ b/src/engine/platform/sound/sn76496.cpp
@@ -158,6 +158,7 @@ sn76496_base_device::sn76496_base_device(
 	: m_feedback_mask(feedbackmask)
 	, m_whitenoise_tap1(noisetap1)
 	, m_whitenoise_tap2(noisetap2)
+  , m_negate(negate)
 	, m_clock_divider(clockdivider)
 	, m_ncr_style_psg(ncr)
 	, m_sega_style_psg(sega)
@@ -165,7 +166,7 @@ sn76496_base_device::sn76496_base_device(
 }
 
 sn76496_device::sn76496_device(const char *tag, uint32_t clock)
-	: sn76496_base_device(tag, 0x8000, 0x01, 0x08, true, 1, false, false, clock)
+	: sn76496_base_device(tag, 0x8000, 0x01, 0x08, false, 1, false, false, clock)
 {
 }
 
diff --git a/src/engine/song.h b/src/engine/song.h
index a45f700f7..b779a09f2 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -94,4 +94,6 @@ struct DivSong {
   std::vector<DivChannelData*> pat;
   std::vector<DivWavetable*> wave;
   std::vector<DivSample*> sample;
+
+  DivInstrument nullIns;
 };