diff --git a/drivers/firmware/dmi_scan.c b/drivers/firmware/dmi_scan.c
index 0eb6b617f709..015c95a825d3 100644
--- a/drivers/firmware/dmi_scan.c
+++ b/drivers/firmware/dmi_scan.c
@@ -567,8 +567,13 @@ static int __init dmi_present(const u8 *buf)
 {
 	u32 smbios_ver;
 
+	/*
+	 * The size of this structure is 31 bytes, but we also accept value
+	 * 30 due to a mistake in SMBIOS specification version 2.1.
+	 */
 	if (memcmp(buf, "_SM_", 4) == 0 &&
-	    buf[5] < 32 && dmi_checksum(buf, buf[5])) {
+	    buf[5] >= 30 && buf[5] <= 32 &&
+	    dmi_checksum(buf, buf[5])) {
 		smbios_ver = get_unaligned_be16(buf + 6);
 		smbios_entry_point_size = buf[5];
 		memcpy(smbios_entry_point, buf, smbios_entry_point_size);
@@ -629,7 +634,8 @@ static int __init dmi_present(const u8 *buf)
 static int __init dmi_smbios3_present(const u8 *buf)
 {
 	if (memcmp(buf, "_SM3_", 5) == 0 &&
-	    buf[6] < 32 && dmi_checksum(buf, buf[6])) {
+	    buf[6] >= 24 && buf[6] <= 32 &&
+	    dmi_checksum(buf, buf[6])) {
 		dmi_ver = get_unaligned_be24(buf + 7);
 		dmi_num = 0;			/* No longer specified */
 		dmi_len = get_unaligned_le32(buf + 12);