diff --git a/coreutils/od_bloaty.c b/coreutils/od_bloaty.c
index 0c4740b47..6a532fa9d 100644
--- a/coreutils/od_bloaty.c
+++ b/coreutils/od_bloaty.c
@@ -545,7 +545,8 @@ decode_one_format(const char *s_orig, const char *s, struct tspec *tspec)
 
 		c = *s++;
 		p = strchr(CSIL, *s);
-		if (!p) {
+		/* if *s == NUL, p != NULL! Testcase: "od -tx" */
+		if (!p || *p == '\0') {
 			size = sizeof(int);
 			if (isdigit(s[0])) {
 				size = bb_strtou(s, &end, 0);