diff --git a/techlibs/common/synth.cc b/techlibs/common/synth.cc
index ee2e86de9..555de9fba 100644
--- a/techlibs/common/synth.cc
+++ b/techlibs/common/synth.cc
@@ -76,7 +76,7 @@ struct SynthPass : public ScriptPass
 		log("        synonymous to the end of the command list.\n");
 		log("\n");
 		log("    -abc9\n");
-		log("        use abc9 instead of abc\n");
+		log("        use new ABC9 flow (EXPERIMENTAL)\n");
 		log("\n");
 		log("\n");
 		log("The following commands are executed by this synthesis command:\n");
@@ -174,6 +174,9 @@ struct SynthPass : public ScriptPass
 		if (!design->full_selection())
 			log_cmd_error("This command only operates on fully selected designs!\n");
 
+		if (abc == "abc9" && !lut)
+			log_cmd_error("ABC9 flow only supported for FPGA synthesis (using '-lut' option)");
+
 		log_header(design, "Executing SYNTH pass.\n");
 		log_push();
 
diff --git a/techlibs/ice40/synth_ice40.cc b/techlibs/ice40/synth_ice40.cc
index 5afa042b0..a60829764 100644
--- a/techlibs/ice40/synth_ice40.cc
+++ b/techlibs/ice40/synth_ice40.cc
@@ -97,7 +97,7 @@ struct SynthIce40Pass : public ScriptPass
 		log("        (this feature is experimental and incomplete)\n");
 		log("\n");
 		log("    -abc9\n");
-		log("        use abc9 instead of abc\n");
+		log("        use new ABC9 flow (EXPERIMENTAL)\n");
 		log("\n");
 		log("\n");
 		log("The following commands are executed by this synthesis command:\n");
diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc
index 3ac19e498..69a3d99c2 100644
--- a/techlibs/xilinx/synth_xilinx.cc
+++ b/techlibs/xilinx/synth_xilinx.cc
@@ -82,7 +82,7 @@ struct SynthXilinxPass : public ScriptPass
 		log("        run 'abc' with -dff option\n");
 		log("\n");
 		log("    -abc9\n");
-		log("        use abc9 instead of abc\n");
+		log("        use new ABC9 flow (EXPERIMENTAL)\n");
 		log("\n");
 		log("\n");
 		log("The following commands are executed by this synthesis command:\n");