diff --git a/cc/proto.go b/cc/proto.go
index c53dcf405..42bb53695 100644
--- a/cc/proto.go
+++ b/cc/proto.go
@@ -115,7 +115,7 @@ func protoFlags(ctx ModuleContext, flags Flags, p *android.ProtoProperties) Flag
 	flags.protoFlags = android.ProtoFlags(ctx, p)
 
 	if proptools.String(p.Proto.Type) == "lite" {
-		flags.protoOutParams = []string{"lite"}
+		flags.protoOutParams = append(flags.protoOutParams, "lite")
 	}
 
 	return flags
diff --git a/cc/util.go b/cc/util.go
index aaf0f71c8..1e4a0c0ca 100644
--- a/cc/util.go
+++ b/cc/util.go
@@ -67,7 +67,7 @@ func flagsToBuilderFlags(in Flags) builderFlags {
 		cppFlags:       strings.Join(in.CppFlags, " "),
 		yaccFlags:      strings.Join(in.YaccFlags, " "),
 		protoFlags:     strings.Join(in.protoFlags, " "),
-		protoOutParams: strings.Join(in.protoOutParams, ":"),
+		protoOutParams: strings.Join(in.protoOutParams, ","),
 		aidlFlags:      strings.Join(in.aidlFlags, " "),
 		rsFlags:        strings.Join(in.rsFlags, " "),
 		ldFlags:        strings.Join(in.LdFlags, " "),