diff --git a/src/engine/platform/genesisext.cpp b/src/engine/platform/genesisext.cpp
index 4d4935b5..cc4abc88 100644
--- a/src/engine/platform/genesisext.cpp
+++ b/src/engine/platform/genesisext.cpp
@@ -179,6 +179,11 @@ int DivPlatformGenesisExt::dispatch(DivCommand c) {
       rWrite(0x22,lfoValue);
       break;
     }
+    case DIV_CMD_FM_FB: {
+      chan[2].state.fb=c.value&7;
+      rWrite(chanOffs[2]+ADDR_FB_ALG,(chan[2].state.alg&7)|(chan[2].state.fb<<3));
+      break;
+    }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
       DivInstrumentFM::Operator& op=chan[2].state.op[orderedOps[c.value]];
diff --git a/src/engine/platform/ym2203ext.cpp b/src/engine/platform/ym2203ext.cpp
index 929687fe..95937207 100644
--- a/src/engine/platform/ym2203ext.cpp
+++ b/src/engine/platform/ym2203ext.cpp
@@ -155,6 +155,11 @@ int DivPlatformYM2203Ext::dispatch(DivCommand c) {
       rWrite(0x22,(c.value&7)|((c.value>>4)<<3));
       break;
     }
+    case DIV_CMD_FM_FB: {
+      chan[2].state.fb=c.value&7;
+      rWrite(chanOffs[2]+ADDR_FB_ALG,(chan[2].state.alg&7)|(chan[2].state.fb<<3));
+      break;
+    }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
       DivInstrument* ins=parent->getIns(opChan[ch].ins,DIV_INS_FM);
diff --git a/src/engine/platform/ym2608ext.cpp b/src/engine/platform/ym2608ext.cpp
index 285e350d..441640b4 100644
--- a/src/engine/platform/ym2608ext.cpp
+++ b/src/engine/platform/ym2608ext.cpp
@@ -155,6 +155,11 @@ int DivPlatformYM2608Ext::dispatch(DivCommand c) {
       rWrite(0x22,(c.value&7)|((c.value>>4)<<3));
       break;
     }
+    case DIV_CMD_FM_FB: {
+      chan[2].state.fb=c.value&7;
+      rWrite(chanOffs[2]+ADDR_FB_ALG,(chan[2].state.alg&7)|(chan[2].state.fb<<3));
+      break;
+    }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
       DivInstrument* ins=parent->getIns(opChan[ch].ins,DIV_INS_FM);
diff --git a/src/engine/platform/ym2610bext.cpp b/src/engine/platform/ym2610bext.cpp
index 20b56c01..cd7e494b 100644
--- a/src/engine/platform/ym2610bext.cpp
+++ b/src/engine/platform/ym2610bext.cpp
@@ -155,6 +155,11 @@ int DivPlatformYM2610BExt::dispatch(DivCommand c) {
       rWrite(0x22,(c.value&7)|((c.value>>4)<<3));
       break;
     }
+    case DIV_CMD_FM_FB: {
+      chan[2].state.fb=c.value&7;
+      rWrite(chanOffs[2]+ADDR_FB_ALG,(chan[2].state.alg&7)|(chan[2].state.fb<<3));
+      break;
+    }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[2]|opOffs[orderedOps[c.value]];
       DivInstrument* ins=parent->getIns(opChan[ch].ins,DIV_INS_FM);
diff --git a/src/engine/platform/ym2610ext.cpp b/src/engine/platform/ym2610ext.cpp
index a3d5df21..bf6df44e 100644
--- a/src/engine/platform/ym2610ext.cpp
+++ b/src/engine/platform/ym2610ext.cpp
@@ -155,6 +155,11 @@ int DivPlatformYM2610Ext::dispatch(DivCommand c) {
       rWrite(0x22,(c.value&7)|((c.value>>4)<<3));
       break;
     }
+    case DIV_CMD_FM_FB: {
+      chan[1].state.fb=c.value&7;
+      rWrite(chanOffs[1]+ADDR_FB_ALG,(chan[1].state.alg&7)|(chan[1].state.fb<<3));
+      break;
+    }
     case DIV_CMD_FM_MULT: { // TODO
       unsigned short baseAddr=chanOffs[1]|opOffs[orderedOps[c.value]];
       DivInstrument* ins=parent->getIns(opChan[ch].ins,DIV_INS_FM);