diff --git a/src/tools/openpgp-tool.c b/src/tools/openpgp-tool.c
index fd75efe7..25182350 100644
--- a/src/tools/openpgp-tool.c
+++ b/src/tools/openpgp-tool.c
@@ -435,7 +435,7 @@ static int do_dump_do(sc_card_t *card, unsigned int tag)
 		if (sizeof(buffer) != r)
 			return EXIT_FAILURE;
 	} else {
-		util_hex_dump_asc(stdout, buffer, sizeof(buffer), -1);
+		util_hex_dump_asc(stdout, buffer, r, -1);
 	}
 
 	return EXIT_SUCCESS;