diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index f8c307ae7..0436ce2f7 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -31,6 +31,13 @@ enum DivDispatchCmds {
   DIV_CMD_STD_NOISE_FREQ,
   DIV_CMD_STD_NOISE_MODE,
 
+  DIV_CMD_WAVE,
+  
+  DIV_CMD_GB_SWEEP_TIME,
+  DIV_CMD_GB_SWEEP_DIR,
+
+  DIV_ALWAYS_SET_VOLUME,
+
   DIV_CMD_MAX
 };
 
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 046fc24c1..650f908ad 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -18,7 +18,7 @@ struct DivChannelState {
   int vibratoDepth, vibratoRate, vibratoPos, vibratoDir, vibratoFine;
   int tremoloDepth, tremoloRate, tremoloPos;
   unsigned char arp, arpStage, arpTicks;
-  bool doNote, legato, portaStop, keyOn, nowYouCanStop, stopOnOff;
+  bool doNote, legato, portaStop, keyOn, nowYouCanStop, stopOnOff, arpYield;
 
   DivChannelState():
     note(-1),
@@ -40,7 +40,7 @@ struct DivChannelState {
     arp(0),
     arpStage(-1),
     arpTicks(1),
-    doNote(false), legato(false), portaStop(false), keyOn(false), nowYouCanStop(true), stopOnOff(false) {}
+    doNote(false), legato(false), portaStop(false), keyOn(false), nowYouCanStop(true), stopOnOff(false), arpYield(false) {}
 };
 
 class DivEngine {
diff --git a/src/engine/platform/gb.cpp b/src/engine/platform/gb.cpp
index 74e731451..efc5cf01a 100644
--- a/src/engine/platform/gb.cpp
+++ b/src/engine/platform/gb.cpp
@@ -169,11 +169,9 @@ int DivPlatformGB::dispatch(DivCommand c) {
       }
       break;
     case DIV_CMD_VOLUME:
-      if (chan[c.chan].vol!=c.value) {
-        chan[c.chan].vol=c.value;
-        if (c.chan==2) {
-          rWrite(16+c.chan*5+2,gbVolMap[chan[c.chan].vol]);
-        }
+      chan[c.chan].vol=c.value;
+      if (c.chan==2) {
+        rWrite(16+c.chan*5+2,gbVolMap[chan[c.chan].vol]);
       }
       break;
     case DIV_CMD_GET_VOLUME:
@@ -183,6 +181,12 @@ int DivPlatformGB::dispatch(DivCommand c) {
       chan[c.chan].pitch=c.value;
       chan[c.chan].freqChanged=true;
       break;
+    case DIV_CMD_WAVE:
+      if (c.chan!=2) break;
+      chan[c.chan].wave=c.value;
+      updateWave();
+      chan[c.chan].freqChanged=true;
+      break;
     case DIV_CMD_NOTE_PORTA: {
       int destFreq=round(FREQ_BASE/pow(2.0f,((float)c.value2/12.0f)));
       bool return2=false;
@@ -225,6 +229,9 @@ int DivPlatformGB::dispatch(DivCommand c) {
     case DIV_CMD_GET_VOLMAX:
       return 15;
       break;
+    case DIV_ALWAYS_SET_VOLUME:
+      return 1;
+      break;
     default:
       break;
   }
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index 88a04542d..fc3caab59 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -312,6 +312,9 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
       
       break;
     }
+    case DIV_ALWAYS_SET_VOLUME:
+      return 0;
+      break;
     case DIV_CMD_GET_VOLMAX:
       return 127;
       break;
diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index 5232ef942..cd84f7115 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -170,6 +170,9 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
     case DIV_CMD_GET_VOLMAX:
       return 127;
       break;
+    case DIV_ALWAYS_SET_VOLUME:
+      return 0;
+      break;
     case DIV_CMD_PRE_PORTA:
       break;
     default:
diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 9af28b49a..b88415229 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -147,6 +147,9 @@ int DivPlatformSMS::dispatch(DivCommand c) {
     case DIV_CMD_GET_VOLMAX:
       return 15;
       break;
+    case DIV_ALWAYS_SET_VOLUME:
+      return 0;
+      break;
     default:
       break;
   }
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index baba91199..a8b383c1f 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -37,7 +37,14 @@ const char* cmdName[DIV_CMD_MAX]={
   "ARCADE_LFO",
 
   "STD_NOISE_FREQ",
-  "STD_NOISE_MODE"
+  "STD_NOISE_MODE",
+
+  "WAVE",
+  
+  "GB_SWEEP_TIME",
+  "GB_SWEEP_DIR",
+
+  "ALWAYS_SET_VOLUME"
 };
 
 const char* formatNote(unsigned char note, unsigned char octave) {
@@ -83,6 +90,15 @@ bool DivEngine::perSystemEffect(int ch, unsigned char effect, unsigned char effe
           return false;
       }
       break;
+    case DIV_SYSTEM_GB:
+      switch (effect) {
+        case 0x10: // select waveform
+          dispatchCmd(DivCommand(DIV_CMD_WAVE,ch,effectVal));
+          break;
+        default:
+          return false;
+      }
+      break;
     default:
       return false;
   }
@@ -176,11 +192,14 @@ void DivEngine::processRow(int i, bool afterDelay) {
       chan[i].arp=0;
     }
     chan[i].doNote=true;
+    if (chan[i].arp!=0) {
+      chan[i].arpYield=true;
+    }
   }
 
   // volume
   if (pat->data[curRow][3]!=-1) {
-    if ((MIN(chan[i].volMax,chan[i].volume)>>8)!=pat->data[curRow][3]) {
+    if (dispatchCmd(DivCommand(DIV_ALWAYS_SET_VOLUME,i)) || (MIN(chan[i].volMax,chan[i].volume)>>8)!=pat->data[curRow][3]) {
       chan[i].volume=pat->data[curRow][3]<<8;
       dispatchCmd(DivCommand(DIV_CMD_VOLUME,i,chan[i].volume>>8));
     }
@@ -473,7 +492,7 @@ void DivEngine::nextTick() {
         dispatchCmd(DivCommand(DIV_CMD_NOTE_OFF,i));
       }
     }
-    if (chan[i].arp!=0 && chan[i].portaSpeed<1) {
+    if (chan[i].arp!=0 && !chan[i].arpYield && chan[i].portaSpeed<1) {
       if (--chan[i].arpTicks<1) {
         chan[i].arpTicks=song.arpLen;
         chan[i].arpStage++;
@@ -490,6 +509,8 @@ void DivEngine::nextTick() {
             break;
         }
       }
+    } else {
+      chan[i].arpYield=false;
     }
   }