diff --git a/src/engine/platform/vb.cpp b/src/engine/platform/vb.cpp
index 29ff6a93..941f72eb 100644
--- a/src/engine/platform/vb.cpp
+++ b/src/engine/platform/vb.cpp
@@ -148,6 +148,13 @@ void DivPlatformVB::tick(bool sysTick) {
       }
       chan[i].freqChanged=true;
     }
+    if (i==5 && chan[i].std.duty.had) {
+      if ((chan[i].std.duty.val&7)!=((chan[i].envHigh>>4)&7)) {
+        chan[i].envHigh&=~0x70;
+        chan[i].envHigh|=(chan[i].std.duty.val&7)<<4;
+        writeEnv(i,true);
+      }
+    }
     if (chan[i].std.wave.had) {
       if (chan[i].wave!=chan[i].std.wave.val || chan[i].ws.activeChanged()) {
         chan[i].wave=chan[i].std.wave.val;
diff --git a/src/gui/insEdit.cpp b/src/gui/insEdit.cpp
index 0f0d0d7f..6b98ba71 100644
--- a/src/gui/insEdit.cpp
+++ b/src/gui/insEdit.cpp
@@ -4702,9 +4702,13 @@ void FurnaceGUI::drawInsEdit() {
           }
           if (ins->type==DIV_INS_TIA || ins->type==DIV_INS_AMIGA || ins->type==DIV_INS_SCC ||
               ins->type==DIV_INS_PET || ins->type==DIV_INS_VIC || ins->type==DIV_INS_SEGAPCM ||
-              ins->type==DIV_INS_FM || ins->type==DIV_INS_VBOY) {
+              ins->type==DIV_INS_FM) {
             dutyMax=0;
           }
+          if (ins->type==DIV_INS_VBOY) {
+            dutyLabel="Noise Length";
+            dutyMax=7;
+          }
           if (ins->type==DIV_INS_PCE || ins->type==DIV_INS_NAMCO) {
             dutyLabel="Noise";
             dutyMax=(ins->type==DIV_INS_PCE && !ins->amiga.useSample)?1:0;