diff --git a/papers/format.md b/papers/format.md
index bef8b1f8..3e358346 100644
--- a/papers/format.md
+++ b/papers/format.md
@@ -32,6 +32,7 @@ these fields are 0 in format versions prior to 100 (0.6pre1).
 
 the format versions are:
 
+- 101: Furnace 0.6pre1 (dev101)
 - 100: Furnace 0.6pre1
 - 99: Furnace dev99
 - 98: Furnace dev98
@@ -318,7 +319,8 @@ size | description
   1  | volume macro still applies after end (>=99) or reserved
   1  | broken outVol (>=99) or reserved
   1  | E1xy and E2xy stop on same note (>=100) or reserved
-  8  | reserved
+  1  | broken initial position of porta after arp (>=101) or reserved
+  7  | reserved
  --- | **virtual tempo data**
   2  | virtual tempo numerator of first song (>=96) or reserved
   2  | virtual tempo denominator of first song (>=96) or reserved
diff --git a/src/engine/engine.h b/src/engine/engine.h
index 962e0fcc..5f5ab1a3 100644
--- a/src/engine/engine.h
+++ b/src/engine/engine.h
@@ -45,8 +45,8 @@
 #define BUSY_BEGIN_SOFT softLocked=true; isBusy.lock();
 #define BUSY_END isBusy.unlock(); softLocked=false;
 
-#define DIV_VERSION "0.6pre1"
-#define DIV_ENGINE_VERSION 100
+#define DIV_VERSION "0.6pre1 (dev101)"
+#define DIV_ENGINE_VERSION 101
 
 // for imports
 #define DIV_VERSION_MOD 0xff01
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index d4c45323..ddc5edf6 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -172,6 +172,7 @@ bool DivEngine::loadDMF(unsigned char* file, size_t len) {
     ds.volMacroLinger=false;
     ds.brokenOutVol=true; // ???
     ds.e1e2StopOnSameNote=true;
+    ds.brokenPortaArp=false;
 
     // 1.1 compat flags
     if (ds.version>24) {
@@ -1047,6 +1048,9 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
     if (ds.version<100) {
       ds.e1e2StopOnSameNote=false;
     }
+    if (ds.version<101) {
+      ds.brokenPortaArp=true;
+    }
     ds.isDMF=false;
 
     reader.readS(); // reserved
@@ -1448,7 +1452,12 @@ bool DivEngine::loadFur(unsigned char* file, size_t len) {
       } else {
         reader.readC();
       }
-      for (int i=0; i<8; i++) {
+      if (ds.version>=101) {
+        ds.brokenPortaArp=reader.readC();
+      } else {
+        reader.readC();
+      }
+      for (int i=0; i<7; i++) {
         reader.readC();
       }
     }
@@ -2922,7 +2931,8 @@ SafeWriter* DivEngine::saveFur(bool notPrimary) {
   w->writeC(song.volMacroLinger);
   w->writeC(song.brokenOutVol);
   w->writeC(song.e1e2StopOnSameNote);
-  for (int i=0; i<8; i++) {
+  w->writeC(song.brokenPortaArp);
+  for (int i=0; i<7; i++) {
     w->writeC(0);
   }
 
diff --git a/src/engine/platform/amiga.cpp b/src/engine/platform/amiga.cpp
index 8037feaf..65b44136 100644
--- a/src/engine/platform/amiga.cpp
+++ b/src/engine/platform/amiga.cpp
@@ -355,6 +355,7 @@ int DivPlatformAmiga::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AMIGA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_SAMPLE_POS:
diff --git a/src/engine/platform/arcade.cpp b/src/engine/platform/arcade.cpp
index 1be61fa2..41042cd5 100644
--- a/src/engine/platform/arcade.cpp
+++ b/src/engine/platform/arcade.cpp
@@ -827,6 +827,7 @@ int DivPlatformArcade::dispatch(DivCommand c) {
       return 127;
       break;
     case DIV_CMD_PRE_PORTA:
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_LINEAR(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/ay.cpp b/src/engine/platform/ay.cpp
index 07377610..7018824b 100644
--- a/src/engine/platform/ay.cpp
+++ b/src/engine/platform/ay.cpp
@@ -474,6 +474,7 @@ int DivPlatformAY8910::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AY));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/ay8930.cpp b/src/engine/platform/ay8930.cpp
index 0fad4025..581ebb9e 100644
--- a/src/engine/platform/ay8930.cpp
+++ b/src/engine/platform/ay8930.cpp
@@ -506,6 +506,7 @@ int DivPlatformAY8930::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AY8930));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/bubsyswsg.cpp b/src/engine/platform/bubsyswsg.cpp
index 48a07880..5fe4462f 100644
--- a/src/engine/platform/bubsyswsg.cpp
+++ b/src/engine/platform/bubsyswsg.cpp
@@ -250,6 +250,7 @@ int DivPlatformBubSysWSG::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_SCC));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/c64.cpp b/src/engine/platform/c64.cpp
index a55b5390..640df54e 100644
--- a/src/engine/platform/c64.cpp
+++ b/src/engine/platform/c64.cpp
@@ -369,6 +369,7 @@ int DivPlatformC64::dispatch(DivCommand c) {
           chan[c.chan].keyOn=true;
         }
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/fds.cpp b/src/engine/platform/fds.cpp
index ea4b83e9..f9fc5b50 100644
--- a/src/engine/platform/fds.cpp
+++ b/src/engine/platform/fds.cpp
@@ -406,6 +406,7 @@ int DivPlatformFDS::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_FDS));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/gb.cpp b/src/engine/platform/gb.cpp
index 999d31b9..2b7dcf6d 100644
--- a/src/engine/platform/gb.cpp
+++ b/src/engine/platform/gb.cpp
@@ -393,6 +393,7 @@ int DivPlatformGB::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_GB));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GB_SWEEP_DIR:
diff --git a/src/engine/platform/lynx.cpp b/src/engine/platform/lynx.cpp
index 4fd30db9..3f5e92c0 100644
--- a/src/engine/platform/lynx.cpp
+++ b/src/engine/platform/lynx.cpp
@@ -387,6 +387,7 @@ int DivPlatformLynx::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_MIKEY));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/mmc5.cpp b/src/engine/platform/mmc5.cpp
index 2b97f46f..dc9e5aba 100644
--- a/src/engine/platform/mmc5.cpp
+++ b/src/engine/platform/mmc5.cpp
@@ -324,6 +324,7 @@ int DivPlatformMMC5::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_STD));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/n163.cpp b/src/engine/platform/n163.cpp
index 50f9d836..b20b460e 100644
--- a/src/engine/platform/n163.cpp
+++ b/src/engine/platform/n163.cpp
@@ -562,6 +562,7 @@ int DivPlatformN163::dispatch(DivCommand c) {
           chan[c.chan].keyOn=true;
         }
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/namcowsg.cpp b/src/engine/platform/namcowsg.cpp
index 6bcf43d2..00b12793 100644
--- a/src/engine/platform/namcowsg.cpp
+++ b/src/engine/platform/namcowsg.cpp
@@ -442,6 +442,7 @@ int DivPlatformNamcoWSG::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_PCE));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/nes.cpp b/src/engine/platform/nes.cpp
index 67ad2852..d801fe66 100644
--- a/src/engine/platform/nes.cpp
+++ b/src/engine/platform/nes.cpp
@@ -573,6 +573,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_STD));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/opl.cpp b/src/engine/platform/opl.cpp
index 9373d0cd..823e764b 100644
--- a/src/engine/platform/opl.cpp
+++ b/src/engine/platform/opl.cpp
@@ -1434,6 +1434,9 @@ int DivPlatformOPL::dispatch(DivCommand c) {
       return 63;
       break;
     case DIV_CMD_PRE_PORTA:
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) {
+        chan[c.chan].baseFreq=(c.chan==adpcmChan)?(NOTE_ADPCMB(chan[c.chan].note)):(NOTE_FREQUENCY(chan[c.chan].note));
+      }
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/opll.cpp b/src/engine/platform/opll.cpp
index 08292be6..5c9611b4 100644
--- a/src/engine/platform/opll.cpp
+++ b/src/engine/platform/opll.cpp
@@ -831,6 +831,7 @@ int DivPlatformOPLL::dispatch(DivCommand c) {
       break;
     case DIV_CMD_PRE_PORTA:
       if (c.chan>=9 && !properDrums) return 0;
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/pce.cpp b/src/engine/platform/pce.cpp
index b8c580e5..9e1302a0 100644
--- a/src/engine/platform/pce.cpp
+++ b/src/engine/platform/pce.cpp
@@ -445,6 +445,7 @@ int DivPlatformPCE::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_PCE));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/pcspkr.cpp b/src/engine/platform/pcspkr.cpp
index 57c72b67..d40a297a 100644
--- a/src/engine/platform/pcspkr.cpp
+++ b/src/engine/platform/pcspkr.cpp
@@ -471,6 +471,7 @@ int DivPlatformPCSpeaker::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_BEEPER));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/pet.cpp b/src/engine/platform/pet.cpp
index 9b3c9988..49343627 100644
--- a/src/engine/platform/pet.cpp
+++ b/src/engine/platform/pet.cpp
@@ -239,6 +239,7 @@ int DivPlatformPET::dispatch(DivCommand c) {
       if (chan.active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan.macroInit(parent->getIns(chan.ins,DIV_INS_PET));
       }
+      if (!chan.inPorta && c.value && !parent->song.brokenPortaArp && chan.std.arp.will) chan.baseFreq=NOTE_PERIODIC(chan.note);
       chan.inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/qsound.cpp b/src/engine/platform/qsound.cpp
index 8af565df..6eb14be7 100644
--- a/src/engine/platform/qsound.cpp
+++ b/src/engine/platform/qsound.cpp
@@ -496,6 +496,7 @@ int DivPlatformQSound::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AMIGA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=QS_NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/rf5c68.cpp b/src/engine/platform/rf5c68.cpp
index 2106a5a7..176b6e7c 100644
--- a/src/engine/platform/rf5c68.cpp
+++ b/src/engine/platform/rf5c68.cpp
@@ -265,6 +265,7 @@ int DivPlatformRF5C68::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AMIGA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_SAMPLE_POS:
diff --git a/src/engine/platform/saa.cpp b/src/engine/platform/saa.cpp
index c562838a..103c3348 100644
--- a/src/engine/platform/saa.cpp
+++ b/src/engine/platform/saa.cpp
@@ -335,6 +335,7 @@ int DivPlatformSAA1099::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_SAA1099));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/scc.cpp b/src/engine/platform/scc.cpp
index 8175bc01..485839bf 100644
--- a/src/engine/platform/scc.cpp
+++ b/src/engine/platform/scc.cpp
@@ -267,6 +267,7 @@ int DivPlatformSCC::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_SCC));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/segapcm.cpp b/src/engine/platform/segapcm.cpp
index 19b8eb82..71d45298 100644
--- a/src/engine/platform/segapcm.cpp
+++ b/src/engine/platform/segapcm.cpp
@@ -365,6 +365,7 @@ int DivPlatformSegaPCM::dispatch(DivCommand c) {
       return 127;
       break;
     case DIV_CMD_PRE_PORTA:
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=(chan[c.chan].note<<6);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/sms.cpp b/src/engine/platform/sms.cpp
index 28462027..3d11a5ac 100644
--- a/src/engine/platform/sms.cpp
+++ b/src/engine/platform/sms.cpp
@@ -353,9 +353,8 @@ int DivPlatformSMS::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_STD));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
-      // TODO: pre porta cancel arp compat flag
-      //if (chan[c.chan].inPorta) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       break;
     case DIV_CMD_GET_VOLMAX:
       return 15;
diff --git a/src/engine/platform/su.cpp b/src/engine/platform/su.cpp
index c6860afb..f3be01a7 100644
--- a/src/engine/platform/su.cpp
+++ b/src/engine/platform/su.cpp
@@ -454,6 +454,7 @@ int DivPlatformSoundUnit::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_SU));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/swan.cpp b/src/engine/platform/swan.cpp
index 905fa82a..b3e83319 100644
--- a/src/engine/platform/swan.cpp
+++ b/src/engine/platform/swan.cpp
@@ -431,6 +431,7 @@ int DivPlatformSwan::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_SWAN));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/tia.cpp b/src/engine/platform/tia.cpp
index da347244..ddb38084 100644
--- a/src/engine/platform/tia.cpp
+++ b/src/engine/platform/tia.cpp
@@ -259,6 +259,7 @@ int DivPlatformTIA::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_TIA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=(chan[c.chan].note<<8);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/tx81z.cpp b/src/engine/platform/tx81z.cpp
index 123d1193..9d24e4db 100644
--- a/src/engine/platform/tx81z.cpp
+++ b/src/engine/platform/tx81z.cpp
@@ -933,6 +933,7 @@ int DivPlatformTX81Z::dispatch(DivCommand c) {
       return 127;
       break;
     case DIV_CMD_PRE_PORTA:
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_LINEAR(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_PRE_NOTE:
diff --git a/src/engine/platform/vera.cpp b/src/engine/platform/vera.cpp
index 62e1ea68..092bbb6a 100644
--- a/src/engine/platform/vera.cpp
+++ b/src/engine/platform/vera.cpp
@@ -359,6 +359,7 @@ int DivPlatformVERA::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_VERA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=calcNoteFreq(c.chan,chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_STD_NOISE_MODE:
diff --git a/src/engine/platform/vic20.cpp b/src/engine/platform/vic20.cpp
index 8475b0e5..771b87d1 100644
--- a/src/engine/platform/vic20.cpp
+++ b/src/engine/platform/vic20.cpp
@@ -243,6 +243,7 @@ int DivPlatformVIC20::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_VIC));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/vrc6.cpp b/src/engine/platform/vrc6.cpp
index 08c6d053..88fcb37b 100644
--- a/src/engine/platform/vrc6.cpp
+++ b/src/engine/platform/vrc6.cpp
@@ -399,6 +399,7 @@ int DivPlatformVRC6::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_VRC6));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_PERIODIC(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/platform/x1_010.cpp b/src/engine/platform/x1_010.cpp
index dc5c7ed2..e2e360b1 100644
--- a/src/engine/platform/x1_010.cpp
+++ b/src/engine/platform/x1_010.cpp
@@ -732,6 +732,7 @@ int DivPlatformX1_010::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_X1_010));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NoteX1_010(c.chan,chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_SAMPLE_FREQ:
diff --git a/src/engine/platform/ymz280b.cpp b/src/engine/platform/ymz280b.cpp
index 45631a94..d8d98478 100644
--- a/src/engine/platform/ymz280b.cpp
+++ b/src/engine/platform/ymz280b.cpp
@@ -293,6 +293,7 @@ int DivPlatformYMZ280B::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_AMIGA));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_SAMPLE_POS:
diff --git a/src/engine/platform/zxbeeper.cpp b/src/engine/platform/zxbeeper.cpp
index 524d3c11..01702dc5 100644
--- a/src/engine/platform/zxbeeper.cpp
+++ b/src/engine/platform/zxbeeper.cpp
@@ -224,6 +224,7 @@ int DivPlatformZXBeeper::dispatch(DivCommand c) {
       if (chan[c.chan].active && c.value2) {
         if (parent->song.resetMacroOnPorta) chan[c.chan].macroInit(parent->getIns(chan[c.chan].ins,DIV_INS_BEEPER));
       }
+      if (!chan[c.chan].inPorta && c.value && !parent->song.brokenPortaArp && chan[c.chan].std.arp.will) chan[c.chan].baseFreq=NOTE_FREQUENCY(chan[c.chan].note);
       chan[c.chan].inPorta=c.value;
       break;
     case DIV_CMD_GET_VOLMAX:
diff --git a/src/engine/song.h b/src/engine/song.h
index d06c5737..185cac8a 100644
--- a/src/engine/song.h
+++ b/src/engine/song.h
@@ -497,6 +497,7 @@ struct DivSong {
   bool volMacroLinger;
   bool brokenOutVol;
   bool e1e2StopOnSameNote;
+  bool brokenPortaArp;
 
   std::vector<DivInstrument*> ins;
   std::vector<DivWavetable*> wave;
@@ -595,7 +596,8 @@ struct DivSong {
     newVolumeScaling(true),
     volMacroLinger(true),
     brokenOutVol(false),
-    e1e2StopOnSameNote(false) {
+    e1e2StopOnSameNote(false),
+    brokenPortaArp(false) {
     for (int i=0; i<32; i++) {
       system[i]=DIV_SYSTEM_NULL;
       systemVol[i]=64;
diff --git a/src/gui/compatFlags.cpp b/src/gui/compatFlags.cpp
index 8e5d7517..9024992e 100644
--- a/src/gui/compatFlags.cpp
+++ b/src/gui/compatFlags.cpp
@@ -207,31 +207,35 @@ void FurnaceGUI::drawCompatFlags() {
     }
     ImGui::Checkbox("Stop portamento on note off",&e->song.stopPortaOnNoteOff);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("Allow instrument change during slides",&e->song.newInsTriggersInPorta);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("Reset note to base on arpeggio stop",&e->song.arp0Reset);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("ExtCh channel status is shared among operators",&e->song.sharedExtStat);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("New SegaPCM features (macros and better panning)",&e->song.newSegaPCM);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("Old FM octave boundary behavior",&e->song.oldOctaveBoundary);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
     }
     ImGui::Checkbox("No OPN2 DAC volume control",&e->song.noOPN2Vol);
     if (ImGui::IsItemHovered()) {
-      ImGui::SetTooltip("behavior changed in 0.6");
+      ImGui::SetTooltip("behavior changed in 0.6pre1");
+    }
+    ImGui::Checkbox("Broken initial position of portamento after arpeggio",&e->song.brokenPortaArp);
+    if (ImGui::IsItemHovered()) {
+      ImGui::SetTooltip("behavior changed in 0.6pre1.5");
     }
   }
   if (ImGui::IsWindowFocused(ImGuiFocusedFlags_ChildWindows)) curWindow=GUI_WINDOW_COMPAT_FLAGS;