diff --git a/sys/dev/mmc/mmc_helpers.c b/sys/dev/mmc/mmc_helpers.c
--- a/sys/dev/mmc/mmc_helpers.c
+++ b/sys/dev/mmc/mmc_helpers.c
@@ -105,9 +105,9 @@
 	 * if it's not present based on the clock that the mmc controller
 	 * operates on
 	 */
-	max_freq = 0;
-	device_get_property(dev, "max-frequency", &max_freq, sizeof(uint64_t));
-	host->f_max = max_freq;
+	if (device_get_property(dev, "max-frequency", &max_freq,
+	    sizeof(uint64_t)) > 0)
+		host->f_max = max_freq;
 
 	if (device_has_property(dev, "broken-cd"))
 		helper->props |= MMC_PROP_BROKEN_CD;