diff --git a/doc/7-systems/c64.md b/doc/7-systems/c64.md
index 28a69671b..1688f5e70 100644
--- a/doc/7-systems/c64.md
+++ b/doc/7-systems/c64.md
@@ -47,6 +47,7 @@ two versions of aforementioned chip exist - 6581 (original chip) and 8580 (impro
   - if `y` is not 0: now
   - this effect is not necessary if the instrument's duty macro is absolute.
 - `1Exy`: **change additional parameters.**
+  - _this effect only exists for compatibility reasons, and its use is discouraged._
   - `x` may be one of the following:
     - `0`: attack (`y` from `0` to `F`)
     - `1`: decay (`y` from `0` to `F`)
@@ -55,6 +56,12 @@ two versions of aforementioned chip exist - 6581 (original chip) and 8580 (impro
     - `4`: ring modulation (`y` is `0` or `1`)
     - `5`: oscillator sync (`y` is `0` or `1`)
     - `6`: disable channel 3 (`y` is `0` or `1`)
+- `20xy`: **set attack/decay.**
+  - `x` is the attack.
+  - `y` is the decay.
+- `21xy`: **set sustain/release.**
+  - `x` is the sustain.
+  - `y` is the release.
 - `3xxx`: **set duty cycle.** `xxx` range is `000` to `FFF`.
 - `4xxx`: **set cutoff.** `xxx` range is `000` to `7FF`.
 
diff --git a/src/engine/dispatch.h b/src/engine/dispatch.h
index 3f2dda6b1..6f2119356 100644
--- a/src/engine/dispatch.h
+++ b/src/engine/dispatch.h
@@ -238,6 +238,9 @@ enum DivDispatchCmds {
 
   DIV_CMD_EXTERNAL, // (value)
 
+  DIV_CMD_C64_AD, // (value)
+  DIV_CMD_C64_SR, // (value)
+
   DIV_ALWAYS_SET_VOLUME, // () -> alwaysSetVol
 
   DIV_CMD_MAX
diff --git a/src/engine/platform/c64.cpp b/src/engine/platform/c64.cpp
index a7e2e3e03..cfabd2049 100644
--- a/src/engine/platform/c64.cpp
+++ b/src/engine/platform/c64.cpp
@@ -493,6 +493,16 @@ int DivPlatformC64::dispatch(DivCommand c) {
           break;
       }
       break;
+    case DIV_CMD_C64_AD:
+      chan[c.chan].attack=c.value>>4;
+      chan[c.chan].decay=c.value&15;
+      rWrite(c.chan*7+5,(chan[c.chan].attack<<4)|(chan[c.chan].decay));
+      break;
+    case DIV_CMD_C64_SR:
+      chan[c.chan].sustain=c.value>>4;
+      chan[c.chan].release=c.value&15;
+      rWrite(c.chan*7+6,(chan[c.chan].sustain<<4)|(chan[c.chan].release));
+      break;
     case DIV_CMD_MACRO_OFF:
       chan[c.chan].std.mask(c.value,true);
       break;
diff --git a/src/engine/playback.cpp b/src/engine/playback.cpp
index 438641797..de5c58a22 100644
--- a/src/engine/playback.cpp
+++ b/src/engine/playback.cpp
@@ -239,6 +239,9 @@ const char* cmdName[]={
 
   "EXTERNAL",
 
+  "C64_AD",
+  "C64_SR",
+
   "ALWAYS_SET_VOLUME"
 };
 
diff --git a/src/engine/sysDef.cpp b/src/engine/sysDef.cpp
index d4a58dcad..410a4203b 100644
--- a/src/engine/sysDef.cpp
+++ b/src/engine/sysDef.cpp
@@ -598,6 +598,8 @@ void DivEngine::registerSystems() {
     {0x1b, {DIV_CMD_C64_FILTER_RESET, "1Bxy: Reset cutoff (x: on new note; y: now)"}},
     {0x1c, {DIV_CMD_C64_DUTY_RESET, "1Cxy: Reset pulse width (x: on new note; y: now)"}},
     {0x1e, {DIV_CMD_C64_EXTENDED, "1Exy: Change additional parameters"}},
+    {0x20, {DIV_CMD_C64_AD, "20xy: Set attack/decay (x: attack; y: decay)"}},
+    {0x21, {DIV_CMD_C64_SR, "21xy: Set sustain/release (x: sustain; y: release)"}},
   };
   const EffectHandler c64FineDutyHandler(DIV_CMD_C64_FINE_DUTY, "3xxx: Set pulse width (0 to FFF)", effectValLong<12>);
   const EffectHandler c64FineCutoffHandler(DIV_CMD_C64_FINE_CUTOFF, "4xxx: Set cutoff (0 to 7FF)", effectValLong<11>);