diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index bfe793caa963..154cc5711a4c 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1668,29 +1668,44 @@ int run_stdlib(int min, int max)
 	return ret;
 }
 
-#define EXPECT_VFPRINTF(c, expected, fmt, ...)				\
-	ret += expect_vfprintf(llen, c, expected, fmt, ##__VA_ARGS__)
+#define EXPECT_VFPRINTF(expected, fmt, ...)				\
+	ret += expect_vfprintf(llen, expected, fmt, ##__VA_ARGS__)
 
-static int expect_vfprintf(int llen, int c, const char *expected, const char *fmt, ...)
+#define VFPRINTF_LEN 20
+static int expect_vfprintf(int llen, const char *expected, const char *fmt, ...)
 {
-	char buf[100];
+	char buf[VFPRINTF_LEN + 80];
+	unsigned int cmp_len;
 	va_list args;
-	ssize_t w;
+	ssize_t w, expected_len;
 
 	va_start(args, fmt);
-	/* Only allow writing 21 bytes, to test truncation */
-	w = vsnprintf(buf, 21, fmt, args);
+	/* Limit buffer length to test truncation */
+	w = vsnprintf(buf, VFPRINTF_LEN + 1, fmt, args);
 	va_end(args);
 
 	llen += printf(" \"%s\"", buf);
-	if (strncmp(expected, buf, c)) {
-		llen += printf(" should be \"%s\"", expected);
+
+	expected_len = strlen(expected);
+	if (expected_len > VFPRINTF_LEN) {
+		/* Indicate truncated in test output */
+		llen += printf("+");
+		cmp_len = VFPRINTF_LEN;
+	} else {
+		cmp_len = expected_len;
+	}
+
+	if (memcmp(expected, buf, cmp_len) || buf[cmp_len]) {
+		/* Copy and truncate until "%.*s" supported */
+		memcpy(buf, expected, cmp_len);
+		buf[cmp_len] = 0;
+		llen += printf(" should be \"%s\"", buf);
 		result(llen, FAIL);
 		return 1;
 	}
 
-	if (w != c) {
-		llen += printf(" written(%d) != %d", (int)w, c);
+	if (w != expected_len) {
+		llen += printf(" written(%d) != %d", (int)w, (int)expected_len);
 		result(llen, FAIL);
 		return 1;
 	}
@@ -1817,21 +1832,21 @@ static int run_printf(int min, int max)
 		 * test numbers.
 		 */
 		switch (test + __LINE__ + 1) {
-		CASE_TEST(empty);        EXPECT_VFPRINTF(0, "", ""); break;
-		CASE_TEST(simple);       EXPECT_VFPRINTF(3, "foo", "foo"); break;
-		CASE_TEST(string);       EXPECT_VFPRINTF(3, "foo", "%s", "foo"); break;
-		CASE_TEST(number);       EXPECT_VFPRINTF(4, "1234", "%d", 1234); break;
-		CASE_TEST(negnumber);    EXPECT_VFPRINTF(5, "-1234", "%d", -1234); break;
-		CASE_TEST(unsigned);     EXPECT_VFPRINTF(5, "12345", "%u", 12345); break;
-		CASE_TEST(char);         EXPECT_VFPRINTF(1, "c", "%c", 'c'); break;
-		CASE_TEST(hex);          EXPECT_VFPRINTF(1, "f", "%x", 0xf); break;
-		CASE_TEST(pointer);      EXPECT_VFPRINTF(3, "0x1", "%p", (void *) 0x1); break;
-		CASE_TEST(uintmax_t);    EXPECT_VFPRINTF(20, "18446744073709551615", "%ju", 0xffffffffffffffffULL); break;
-		CASE_TEST(intmax_t);     EXPECT_VFPRINTF(20, "-9223372036854775807", "%jd", 0x8000000000000001LL); break;
-		CASE_TEST(truncation);   EXPECT_VFPRINTF(25, "01234567890123456789", "%s", "0123456789012345678901234"); break;
-		CASE_TEST(string_width); EXPECT_VFPRINTF(10, "         1", "%10s", "1"); break;
-		CASE_TEST(number_width); EXPECT_VFPRINTF(10, "         1", "%10d", 1); break;
-		CASE_TEST(width_trunc);  EXPECT_VFPRINTF(25, "                    ", "%25d", 1); break;
+		CASE_TEST(empty);        EXPECT_VFPRINTF("", ""); break;
+		CASE_TEST(simple);       EXPECT_VFPRINTF("foo", "foo"); break;
+		CASE_TEST(string);       EXPECT_VFPRINTF("foo", "%s", "foo"); break;
+		CASE_TEST(number);       EXPECT_VFPRINTF("1234", "%d", 1234); break;
+		CASE_TEST(negnumber);    EXPECT_VFPRINTF("-1234", "%d", -1234); break;
+		CASE_TEST(unsigned);     EXPECT_VFPRINTF("12345", "%u", 12345); break;
+		CASE_TEST(char);         EXPECT_VFPRINTF("c", "%c", 'c'); break;
+		CASE_TEST(hex);          EXPECT_VFPRINTF("f", "%x", 0xf); break;
+		CASE_TEST(pointer);      EXPECT_VFPRINTF("0x1", "%p", (void *) 0x1); break;
+		CASE_TEST(uintmax_t);    EXPECT_VFPRINTF("18446744073709551615", "%ju", 0xffffffffffffffffULL); break;
+		CASE_TEST(intmax_t);     EXPECT_VFPRINTF("-9223372036854775807", "%jd", 0x8000000000000001LL); break;
+		CASE_TEST(truncation);   EXPECT_VFPRINTF("0123456789012345678901234", "%s", "0123456789012345678901234"); break;
+		CASE_TEST(string_width); EXPECT_VFPRINTF("         1", "%10s", "1"); break;
+		CASE_TEST(number_width); EXPECT_VFPRINTF("         1", "%10d", 1); break;
+		CASE_TEST(width_trunc);  EXPECT_VFPRINTF("                        1", "%25d", 1); break;
 		CASE_TEST(scanf);        EXPECT_ZR(1, test_scanf()); break;
 		CASE_TEST(strerror);     EXPECT_ZR(1, test_strerror()); break;
 		CASE_TEST(printf_error); EXPECT_ZR(1, test_printf_error()); break;