diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index c03f56445..4c0cc3d91 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -1542,7 +1542,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
     case DIV_CMD_FM_ALG:
       if (c.value>7) break;
       chan[c.chan].state.alg=c.value&7;
-      rWrite(ADDR_FB_ALG+chanOffs[c.chan], (chan[c.chan].state.fb&7<<3)|(chan[c.chan].state.alg&7));
+      rWrite(ADDR_FB_ALG+chanOffs[c.chan],(chan[c.chan].state.alg&7)|(chan[c.chan].state.fb<<3));
     default:
       //printf("WARNING: unimplemented command %d\n",c.cmd);
       break;