break;
                case 'A':
                        params.arch = genimg_get_arch_id(optarg);
-                       if (params.arch < 0)
+                       if (params.arch < 0) {
+                               show_valid_options(IH_ARCH);
                                usage("Invalid architecture");
+                       }
                        break;
                case 'b':
                        if (add_content(IH_TYPE_FLATDT, optarg)) {
                        break;
                case 'C':
                        params.comp = genimg_get_comp_id(optarg);
-                       if (params.comp < 0)
+                       if (params.comp < 0) {
+                               show_valid_options(IH_COMP);
                                usage("Invalid compression type");
+                       }
                        break;
                case 'd':
                        params.datafile = optarg;
                        break;
                case 'O':
                        params.os = genimg_get_os_id(optarg);
-                       if (params.os < 0)
+                       if (params.os < 0) {
+                               show_valid_options(IH_OS);
                                usage("Invalid operating system");
+                       }
                        break;
                case 'p':
                        params.external_offset = strtoull(optarg, &ptr, 16);