diff --git a/src/engine/platform/fmshared_OPM.h b/src/engine/platform/fmshared_OPM.h
new file mode 100644
index 000000000..8db58ed98
--- /dev/null
+++ b/src/engine/platform/fmshared_OPM.h
@@ -0,0 +1,9 @@
+#define ADDR_MULT_DT 0x40
+#define ADDR_TL 0x60
+#define ADDR_RS_AR 0x80
+#define ADDR_AM_DR 0xa0
+#define ADDR_DT2_D2R 0xc0
+#define ADDR_SL_RR 0xe0
+#define ADDR_NOTE 0x28
+#define ADDR_KF 0x30
+#define ADDR_LR_FB_ALG 0x20
\ No newline at end of file
diff --git a/src/engine/platform/fmshared_OPN.h b/src/engine/platform/fmshared_OPN.h
new file mode 100644
index 000000000..aa079b536
--- /dev/null
+++ b/src/engine/platform/fmshared_OPN.h
@@ -0,0 +1,16 @@
+#ifndef _FMSHARED_OPN_H
+#define _FMSHARED_OPN_H
+
+#define ADDR_MULT_DT 0x30
+#define ADDR_TL 0x40
+#define ADDR_RS_AR 0x50
+#define ADDR_AM_DR 0x60
+#define ADDR_DT2_D2R 0x70
+#define ADDR_SL_RR 0x80
+#define ADDR_SSG 0x90
+#define ADDR_FREQ 0xa0
+#define ADDR_FREQH 0xa4
+#define ADDR_FB_ALG 0xb0
+#define ADDR_LRAF 0xb4
+
+#endif
\ No newline at end of file
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index e7f705ff2..82217988c 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -100,8 +100,8 @@ void DivPlatformGenesis::tick() {
     if (chan[i].freqChanged) {
       chan[i].freq=parent->calcFreq(chan[i].baseFreq,chan[i].pitch);
       int freqt=toFreq(chan[i].freq);
-      immWrite(chanOffs[i]+0xa4,freqt>>8);
-      immWrite(chanOffs[i]+0xa0,freqt&0xff);
+      immWrite(chanOffs[i]+ADDR_FREQH,freqt>>8);
+      immWrite(chanOffs[i]+ADDR_FREQ,freqt&0xff);
       if (chan[i].furnaceDac) {
         dacRate=(1280000*1.25)/chan[i].baseFreq;
       }
@@ -163,8 +163,7 @@ void DivPlatformGenesis::muteChannel(int ch, bool mute) {
     return;
   }
   isMuted[ch]=mute;
-  DivInstrument* ins=parent->getIns(chan[ch].ins);
-  rWrite(chanOffs[ch]+0xb4,(isMuted[ch]?0:(chan[ch].pan<<6))|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
+  rWrite(chanOffs[ch]+ADDR_LRAF,(isMuted[ch]?0:(chan[ch].pan<<6))|(chan[ch].state.fms&7)|((chan[ch].state.ams&3)<<4));
 }
 
 int DivPlatformGenesis::dispatch(DivCommand c) {
@@ -209,32 +208,36 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           chan[c.chan].furnaceDac=false;
         }
         break;
-      }      
+      }
+
+      if (chan[c.chan].insChanged) {
+        chan[c.chan].state=ins->fm;
+      }
       
       for (int i=0; i<4; i++) {
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];
-        DivInstrumentFM::Operator op=ins->fm.op[i];
-        if (isOutput[ins->fm.alg][i]) {
+        DivInstrumentFM::Operator& op=chan[c.chan].state.op[i];
+        if (isOutput[chan[c.chan].state.alg][i]) {
           if (!chan[c.chan].active || chan[c.chan].insChanged) {
-            rWrite(baseAddr+0x40,127-(((127-op.tl)*(chan[c.chan].vol&0x7f))/127));
+            rWrite(baseAddr+ADDR_TL,127-(((127-op.tl)*(chan[c.chan].vol&0x7f))/127));
           }
         } else {
           if (chan[c.chan].insChanged) {
-            rWrite(baseAddr+0x40,op.tl);
+            rWrite(baseAddr+ADDR_TL,op.tl);
           }
         }
         if (chan[c.chan].insChanged) {
-          rWrite(baseAddr+0x30,(op.mult&15)|(dtTable[op.dt&7]<<4));
-          rWrite(baseAddr+0x50,(op.ar&31)|(op.rs<<6));
-          rWrite(baseAddr+0x60,(op.dr&31)|(op.am<<7));
-          rWrite(baseAddr+0x70,op.d2r&31);
-          rWrite(baseAddr+0x80,(op.rr&15)|(op.sl<<4));
-          rWrite(baseAddr+0x90,op.ssgEnv&15);
+          rWrite(baseAddr+ADDR_MULT_DT,(op.mult&15)|(dtTable[op.dt&7]<<4));
+          rWrite(baseAddr+ADDR_RS_AR,(op.ar&31)|(op.rs<<6));
+          rWrite(baseAddr+ADDR_AM_DR,(op.dr&31)|(op.am<<7));
+          rWrite(baseAddr+ADDR_DT2_D2R,op.d2r&31);
+          rWrite(baseAddr+ADDR_SL_RR,(op.rr&15)|(op.sl<<4));
+          rWrite(baseAddr+ADDR_SSG,op.ssgEnv&15);
         }
       }
       if (chan[c.chan].insChanged) {
-        rWrite(chanOffs[c.chan]+0xb0,(ins->fm.alg&7)|(ins->fm.fb<<3));
-        rWrite(chanOffs[c.chan]+0xb4,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
+        rWrite(chanOffs[c.chan]+ADDR_FB_ALG,(chan[c.chan].state.alg&7)|(chan[c.chan].state.fb<<3));
+        rWrite(chanOffs[c.chan]+ADDR_LRAF,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|(chan[c.chan].state.fms&7)|((chan[c.chan].state.ams&3)<<4));
       }
       chan[c.chan].insChanged=false;
 
@@ -255,14 +258,13 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       break;
     case DIV_CMD_VOLUME: {
       chan[c.chan].vol=c.value;
-      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];
-        if (isOutput[ins->fm.alg][i]) {
-          rWrite(baseAddr+0x40,127-(((127-op.tl)*(chan[c.chan].vol&0x7f))/127));
+        DivInstrumentFM::Operator& op=chan[c.chan].state.op[i];
+        if (isOutput[chan[c.chan].state.alg][i]) {
+          rWrite(baseAddr+ADDR_TL,127-(((127-op.tl)*(chan[c.chan].vol&0x7f))/127));
         } else {
-          rWrite(baseAddr+0x40,op.tl);
+          rWrite(baseAddr+ADDR_TL,op.tl);
         }
       }
       break;
@@ -289,8 +291,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           chan[c.chan].pan=3;
           break;
       }
-      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
-      rWrite(chanOffs[c.chan]+0xb4,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
+      rWrite(chanOffs[c.chan]+ADDR_LRAF,(isMuted[c.chan]?0:(chan[c.chan].pan<<6))|(chan[c.chan].state.fms&7)|((chan[c.chan].state.ams&3)<<4));
       break;
     }
     case DIV_CMD_PITCH: {
@@ -349,33 +350,35 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
     }
     case DIV_CMD_FM_MULT: {
       unsigned short baseAddr=chanOffs[c.chan]|opOffs[orderedOps[c.value]];
-      DivInstrument* ins=parent->getIns(chan[c.chan].ins);
-      DivInstrumentFM::Operator op=ins->fm.op[orderedOps[c.value]];
-      rWrite(baseAddr+0x30,(c.value2&15)|(dtTable[op.dt&7]<<4));
+      DivInstrumentFM::Operator& op=chan[c.chan].state.op[orderedOps[c.value]];
+      op.mult=c.value2&15;
+      rWrite(baseAddr+ADDR_MULT_DT,(op.mult&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->getIns(chan[c.chan].ins);
-      if (isOutput[ins->fm.alg][c.value]) {
-        rWrite(baseAddr+0x40,127-(((127-c.value2)*(chan[c.chan].vol&0x7f))/127));
+      DivInstrumentFM::Operator& op=chan[c.chan].state.op[orderedOps[c.value]];
+      op.tl=c.value2;
+      if (isOutput[chan[c.chan].state.alg][c.value]) {
+        rWrite(baseAddr+ADDR_TL,127-(((127-op.tl)*(chan[c.chan].vol&0x7f))/127));
       } else {
-        rWrite(baseAddr+0x40,c.value2);
+        rWrite(baseAddr+ADDR_TL,op.tl);
       }
       break;
     }
     case DIV_CMD_FM_AR: {
-      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];
+          DivInstrumentFM::Operator& op=chan[c.chan].state.op[i];
+          op.ar=c.value2&31;
           unsigned short baseAddr=chanOffs[c.chan]|opOffs[i];
-          rWrite(baseAddr+0x50,(c.value2&31)|(op.rs<<6));
+          rWrite(baseAddr+ADDR_RS_AR,(op.ar&31)|(op.rs<<6));
         }
       } else {
-        DivInstrumentFM::Operator op=ins->fm.op[orderedOps[c.value]];
+        DivInstrumentFM::Operator& op=chan[c.chan].state.op[orderedOps[c.value]];
+        op.ar=c.value2&31;
         unsigned short baseAddr=chanOffs[c.chan]|opOffs[orderedOps[c.value]];
-        rWrite(baseAddr+0x50,(c.value2&31)|(op.rs<<6));
+        rWrite(baseAddr+ADDR_RS_AR,(op.ar&31)|(op.rs<<6));
       }
       
       break;
diff --git a/src/engine/platform/genesis.h b/src/engine/platform/genesis.h
index 8f8caf4e3..1f929b9ef 100644
--- a/src/engine/platform/genesis.h
+++ b/src/engine/platform/genesis.h
@@ -9,6 +9,7 @@
 class DivPlatformGenesis: public DivDispatch {
   protected:
     struct Channel {
+      DivInstrumentFM state;
       unsigned char freqH, freqL;
       int freq, baseFreq, pitch;
       unsigned char ins;
diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index fb81d8f8d..63075247f 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -17,12 +17,20 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
   switch (c.cmd) {
     case DIV_CMD_NOTE_ON: {
       DivInstrument* ins=parent->getIns(opChan[ch].ins);
+
+      if (opChan[ch].insChanged) {
+        chan[2].state.alg=ins->fm.alg;
+        chan[2].state.fb=ins->fm.fb;
+        chan[2].state.fb=ins->fm.fms;
+        chan[2].state.ams=ins->fm.ams;
+        chan[2].state.op[ordch]=ins->fm.op[ordch];
+      }
       
       unsigned short baseAddr=chanOffs[2]|opOffs[ordch];
-      DivInstrumentFM::Operator op=ins->fm.op[ordch];
+      DivInstrumentFM::Operator& op=chan[2].state.op[ordch];
       if (isOpMuted[ch]) {
         rWrite(baseAddr+0x40,127);
-      } else if (isOutput[ins->fm.alg][ordch]) {
+      } else if (isOutput[chan[2].state.alg][ordch]) {
         if (!opChan[ch].active || opChan[ch].insChanged) {
           rWrite(baseAddr+0x40,127-(((127-op.tl)*(opChan[ch].vol&0x7f))/127));
         }
@@ -40,8 +48,8 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
         rWrite(baseAddr+0x90,op.ssgEnv&15);
       }
       if (opChan[ch].insChanged) { // TODO how does this work?
-        rWrite(chanOffs[2]+0xb0,(ins->fm.alg&7)|(ins->fm.fb<<3));
-        rWrite(chanOffs[2]+0xb4,(opChan[ch].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
+        rWrite(chanOffs[2]+0xb0,(chan[2].state.alg&7)|(chan[2].state.fb<<3));
+        rWrite(chanOffs[2]+0xb4,(opChan[ch].pan<<6)|(chan[2].state.fms&7)|((chan[2].state.ams&3)<<4));
       }
       opChan[ch].insChanged=false;
 
@@ -59,9 +67,8 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       break;
     case DIV_CMD_VOLUME: {
       opChan[ch].vol=c.value;
-      DivInstrument* ins=parent->getIns(opChan[ch].ins);
       unsigned short baseAddr=chanOffs[2]|opOffs[ordch];
-      DivInstrumentFM::Operator op=ins->fm.op[ordch];
+      DivInstrumentFM::Operator& op=chan[2].state.op[ordch];
       if (isOpMuted[ch]) {
         rWrite(baseAddr+0x40,127);
       } else {
@@ -91,9 +98,8 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
           opChan[ch].pan=3;
           break;
       }
-      DivInstrument* ins=parent->getIns(opChan[ch].ins);
       // TODO: ???
-      rWrite(chanOffs[2]+0xb4,(opChan[ch].pan<<6)|(ins->fm.fms&7)|((ins->fm.ams&3)<<4));
+      rWrite(chanOffs[2]+0xb4,(opChan[ch].pan<<6)|(chan[2].state.fms&7)|((chan[2].state.ams&3)<<4));
       break;
     }
     case DIV_CMD_PITCH: {
@@ -141,33 +147,35 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
     }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
-      DivInstrument* ins=parent->getIns(opChan[ch].ins);
-      DivInstrumentFM::Operator op=ins->fm.op[orderedOps[c.value]];
-      rWrite(baseAddr+0x30,(c.value2&15)|(dtTable[op.dt&7]<<4));
+      DivInstrumentFM::Operator& op=chan[2].state.op[orderedOps[c.value]];
+      op.mult=c.value2&15;
+      rWrite(baseAddr+0x30,(op.mult&15)|(dtTable[op.dt&7]<<4));
       break;
     }
     case DIV_CMD_FM_TL: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
-      DivInstrument* ins=parent->getIns(opChan[ch].ins);
-      if (isOutput[ins->fm.alg][c.value]) {
-        rWrite(baseAddr+0x40,127-(((127-c.value2)*(opChan[ch].vol&0x7f))/127));
+      DivInstrumentFM::Operator& op=chan[2].state.op[orderedOps[c.value]];
+      op.tl=c.value2;
+      if (isOutput[chan[2].state.alg][c.value]) {
+        rWrite(baseAddr+0x40,127-(((127-op.tl)*(opChan[ch].vol&0x7f))/127));
       } else {
-        rWrite(baseAddr+0x40,c.value2);
+        rWrite(baseAddr+0x40,op.tl);
       }
       break;
     }
     case DIV_CMD_FM_AR: {
-      DivInstrument* ins=parent->getIns(opChan[ch].ins);
       if (c.value<0)  {
         for (int i=0; i<4; i++) {
-          DivInstrumentFM::Operator op=ins->fm.op[i];
+          DivInstrumentFM::Operator& op=chan[2].state.op[i];
+          op.ar=c.value2&31;
           unsigned short baseAddr=chanOffs[2]|opOffs[i];
-          rWrite(baseAddr+0x50,(c.value2&31)|(op.rs<<6));
+          rWrite(baseAddr+0x50,(op.ar&31)|(op.rs<<6));
         }
       } else {
-        DivInstrumentFM::Operator op=ins->fm.op[orderedOps[c.value]];
+        DivInstrumentFM::Operator& op=chan[2].state.op[orderedOps[c.value]];
+        op.ar=c.value2&31;
         unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
-        rWrite(baseAddr+0x50,(c.value2&31)|(op.rs<<6));
+        rWrite(baseAddr+0x50,(op.ar&31)|(op.rs<<6));
       }
       break;
     }
@@ -198,12 +206,11 @@ void DivPlatformGenesisExt::muteChannel(int ch, bool mute) {
   isOpMuted[ch-2]=mute;
   
   int ordch=orderedOps[ch-2];
-  DivInstrument* ins=parent->getIns(opChan[ch].ins);
   unsigned short baseAddr=chanOffs[2]|opOffs[ordch];
-  DivInstrumentFM::Operator op=ins->fm.op[ordch];
+  DivInstrumentFM::Operator op=chan[2].state.op[ordch];
   if (isOpMuted[ch]) {
     rWrite(baseAddr+0x40,127);
-  } else if (isOutput[ins->fm.alg][ordch]) {
+  } else if (isOutput[chan[2].state.alg][ordch]) {
     rWrite(baseAddr+0x40,127-(((127-op.tl)*(opChan[ch].vol&0x7f))/127));
   } else {
     rWrite(baseAddr+0x40,op.tl);
diff --git a/src/engine/platform/genesisshared.h b/src/engine/platform/genesisshared.h
index 957729cee..512387ee2 100644
--- a/src/engine/platform/genesisshared.h
+++ b/src/engine/platform/genesisshared.h
@@ -25,3 +25,5 @@ static int orderedOps[4]={
 
 #define rWrite(a,v) if (!skipRegisterWrites) {pendingWrites[a]=v;}
 #define immWrite(a,v) if (!skipRegisterWrites) {writes.emplace(a,v); if (dumpWrites) {addWrite(a,v);} }
+
+#include "fmshared_OPN.h"
\ No newline at end of file