diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 655b7f5ed..c16392772 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -72,7 +72,7 @@ const char* DivEngine::getEffectDesc(unsigned char effect, int chan) {
     case 0x0f:
       return "0Fxx: Set speed 2";
     case 0xc0: case 0xc1: case 0xc2: case 0xc3:
-      return "Cxxx: Set tick rate";
+      return "Cxxx: Set tick rate (hz)";
     case 0xe0:
       return "E0xx: Set arp speed";
     case 0xe1:
@@ -97,14 +97,16 @@ const char* DivEngine::getEffectDesc(unsigned char effect, int chan) {
       return "EExx: Send external command";
     case 0xef:
       return "EFxx: Set global tuning (quirky!)";
+    case 0xf0:
+      return "F0xx: Set tick rate (bpm)";
     case 0xf1:
-      return "F1xx: Single note slide up";
+      return "F1xx: Single tick note slide up";
     case 0xf2:
-      return "F2xx: Single note slide down";
+      return "F2xx: Single tick note slide down";
     case 0xf8:
-      return "F8xx: Single volume slide up";
+      return "F8xx: Single tick volume slide up";
     case 0xf9:
-      return "F9xx: Single volume slide down";
+      return "F9xx: Single tick volume slide down";
     case 0xfa:
       return "FAxx: Fast volume slide (0y: down; x0: up)";
     case 0xff:
diff --git a/src/engine/fileOps.cpp b/src/engine/fileOps.cpp
index 5c4154cb8..0d1780458 100644
--- a/src/engine/fileOps.cpp
+++ b/src/engine/fileOps.cpp
@@ -1285,8 +1285,7 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
         if(loopEnd<slen) slen=loopEnd;
         sample->loopStart=loopStart;
       }
-      sample->samples=slen;
-      sample->data8=new signed char[slen];
+      sample->init(slen);
       ds.sample.push_back(sample);
     }
     // orders
@@ -1456,7 +1455,7 @@ bool DivEngine::loadMod(unsigned char* file, size_t len) {
             case 15: // set speed
               // TODO somehow handle VBlank tunes
               if (fxVal>=0x20) {
-                writeFxCol(0xc0,(fxVal*2+2)/5);
+                writeFxCol(0xf0,fxVal);
               } else {
                 writeFxCol(0x09,fxVal);
                 writeFxCol(0x0f,fxVal);
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index d94c18085..b92339d79 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -62,6 +62,7 @@ const char* cmdName[DIV_CMD_MAX]={
   "SAMPLE_MODE",
   "SAMPLE_FREQ",
   "SAMPLE_BANK",
+  "SAMPLE_POS",
 
   "FM_LFO",
   "FM_LFO_WAVE",
@@ -872,9 +873,6 @@ void DivEngine::processRow(int i, bool afterDelay) {
         cycles=((int)(got.rate)<<MASTER_CLOCK_PREC)/divider;
         clockDrift=0;
         break;
-      case 0xc4: // set Hz by tempo
-        // TODO
-        break;
       case 0xe0: // arp speed
         if (effectVal>0) {
           song.arpLen=effectVal;
@@ -947,6 +945,12 @@ void DivEngine::processRow(int i, bool afterDelay) {
       case 0xef: // global pitch
         globalPitch+=(signed char)(effectVal-0x80);
         break;
+      case 0xf0: // set Hz by tempo
+        divider=(effectVal*2+2)/5;
+        if (divider<10) divider=10;
+        cycles=((int)(got.rate)<<MASTER_CLOCK_PREC)/divider;
+        clockDrift=0;
+        break;
       case 0xf1: // single pitch ramp up
       case 0xf2: // single pitch ramp down
         if (effect==0xf1) {
diff --git a/src/gui/pattern.cpp b/src/gui/pattern.cpp
index 38a093409..aed8890ad 100644
--- a/src/gui/pattern.cpp
+++ b/src/gui/pattern.cpp
@@ -62,7 +62,7 @@ const FurnaceGUIColors extFxColors[32]={
   GUI_COLOR_PATTERN_EFFECT_TIME, // ED
   GUI_COLOR_PATTERN_EFFECT_SONG, // EE
   GUI_COLOR_PATTERN_EFFECT_SONG, // EF
-  GUI_COLOR_PATTERN_EFFECT_INVALID, // F0
+  GUI_COLOR_PATTERN_EFFECT_SPEED, // F0
   GUI_COLOR_PATTERN_EFFECT_PITCH, // F1
   GUI_COLOR_PATTERN_EFFECT_PITCH, // F2
   GUI_COLOR_PATTERN_EFFECT_INVALID, // F3