diff --git a/crates/fayalite/src/build/verilog.rs b/crates/fayalite/src/build/verilog.rs
index 7ce77ec..9c54ba8 100644
--- a/crates/fayalite/src/build/verilog.rs
+++ b/crates/fayalite/src/build/verilog.rs
@@ -211,7 +211,7 @@ impl ExternalCommand for UnadjustedVerilog {
         args.write_arg("-o");
         args.write_interned_arg(unadjusted_verilog_file_name);
         if verilog_debug {
-            args.write_args(["-g", "--preserve-values=all"]);
+            args.write_args(["-g", "--preserve-values=named"]);
         }
         if let Some(dialect) = verilog_dialect {
             args.write_args(dialect.firtool_extra_args().iter().copied());