diff --git a/csdr.c b/csdr.c
index 16f488e..930cd8f 100644
--- a/csdr.c
+++ b/csdr.c
@@ -61,8 +61,8 @@ char usage[]=
 "    convert_f_s8\n"
 "    convert_f_s16\n"
 "    convert_s16_f\n"
-"    convert_f_s24\n"
-"    convert_s24_f\n"
+"    convert_f_s24 [--bigendian]\n"
+"    convert_s24_f [--bigendian]\n"
 "    realpart_cf\n"
 "    clipdetect_ff\n"
 "    limit_ff [max_amplitude]\n"