diff --git a/src/engine/platform/pet.cpp b/src/engine/platform/pet.cpp
index bbc0562c..b89f9510 100644
--- a/src/engine/platform/pet.cpp
+++ b/src/engine/platform/pet.cpp
@@ -74,24 +74,11 @@ void DivPlatformPET::acquire(short* bufL, short* bufR, size_t start, size_t len)
   }
 }
 
-void DivPlatformPET::updateWave() {
-  DivWavetable* wt=parent->getWave(chan.wave);
-  if (wt->max<1 || wt->len<1) {
-    rWrite(10,0);
-  } else {
-    unsigned char sr=0;
-    for (int i=0; i<8; i++) {
-      sr=(sr<<1)|((wt->data[i*wt->len/8]*2)/(wt->max+1));
-    }
-    rWrite(10,sr);
-  }
-}
-
 void DivPlatformPET::writeOutVol() {
   if (chan.active && !isMuted && chan.outVol>0) {
     if (regPool[11]!=16) {
       rWrite(11,16);
-      rWrite(10,regPool[10]);
+      rWrite(10,chan.wave);
     }
   } else {
     rWrite(11,0);
@@ -122,7 +109,7 @@ void DivPlatformPET::tick() {
   if (chan.std.hadWave) {
     if (chan.wave!=chan.std.wave) {
       chan.wave=chan.std.wave;
-      updateWave();
+      rWrite(10,chan.wave);
     }
   }
   if (chan.freqChanged || chan.keyOn || chan.keyOff) {
@@ -135,10 +122,6 @@ void DivPlatformPET::tick() {
         chan.outVol=chan.vol;
         writeOutVol();
       }
-      if (chan.wave<0) {
-        chan.wave=0;
-        updateWave();
-      }
       chan.keyOn=false;
     }
     if (chan.keyOff) {
@@ -195,8 +178,7 @@ int DivPlatformPET::dispatch(DivCommand c) {
       break;
     case DIV_CMD_WAVE:
       chan.wave=c.value;
-      updateWave();
-      chan.keyOn=true;
+      rWrite(10,chan.wave);
       break;
     case DIV_CMD_NOTE_PORTA: {
       int destFreq=NOTE_PERIODIC(c.value2);
@@ -252,7 +234,6 @@ void DivPlatformPET::muteChannel(int ch, bool mute) {
 void DivPlatformPET::forceIns() {
   chan.insChanged=true;
   chan.freqChanged=true;
-  updateWave();
   writeOutVol();
 }
 
@@ -271,19 +252,12 @@ int DivPlatformPET::getRegisterPoolSize() {
 void DivPlatformPET::reset() {
   memset(regPool,0,16);
   chan=Channel();
-  chan.vol=1;
 }
 
 bool DivPlatformPET::isStereo() {
   return false;
 }
 
-void DivPlatformPET::notifyWaveChange(int wave) {
-  if (chan.wave==wave) {
-    updateWave();
-  }
-}
-
 void DivPlatformPET::notifyInsDeletion(void* ins) {
   chan.std.notifyInsDeletion((DivInstrument*)ins);
 }
diff --git a/src/engine/platform/pet.h b/src/engine/platform/pet.h
index bc0a815b..3b6af48d 100644
--- a/src/engine/platform/pet.h
+++ b/src/engine/platform/pet.h
@@ -47,7 +47,7 @@ class DivPlatformPET: public DivDispatch {
       inPorta(false),
       vol(1),
       outVol(1),
-      wave(-1),
+      wave(0b00001111),
       sreg(0),
       cnt(0),
       out(0) {}
@@ -56,7 +56,6 @@ class DivPlatformPET: public DivDispatch {
   bool isMuted;
 
   unsigned char regPool[16];
-  void updateWave();
   friend void putDispatchChan(void*,int,int);
   public:
     void acquire(short* bufL, short* bufR, size_t start, size_t len);
@@ -68,7 +67,6 @@ class DivPlatformPET: public DivDispatch {
     void forceIns();
     void tick();
     void muteChannel(int ch, bool mute);
-    void notifyWaveChange(int wave);
     void notifyInsDeletion(void* ins);
     bool isStereo();
     void poke(unsigned int addr, unsigned short val);
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 5d1e23ca..1143e4fe 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -1612,8 +1612,13 @@ void FurnaceGUI::drawInsEdit() {
           if (ins->type==DIV_INS_SAA1099) waveMax=2;
           if (ins->type==DIV_INS_FM || ins->type==DIV_INS_OPLL || ins->type==DIV_INS_OPL || ins->type==DIV_INS_OPZ) waveMax=0;
           if (ins->type==DIV_INS_MIKEY) waveMax=0;
+          if (ins->type==DIV_INS_PET) {
+            waveMax=8;
+            bitMode=true;
+          }
 
-          const char** waveNames=ayShapeBits;
+          const char** waveNames=NULL;
+          if (ins->type==DIV_INS_AY || ins->type==DIV_INS_AY8930 || ins->type==DIV_INS_SAA1099) waveNames=ayShapeBits;
           if (ins->type==DIV_INS_C64) waveNames=c64ShapeBits;
 
           int ex1Max=(ins->type==DIV_INS_AY8930)?8:0;