diff --git a/doc/scst_user_spec.txt b/doc/scst_user_spec.txt
index 985ca2cd7..beb789482 100644
--- a/doc/scst_user_spec.txt
+++ b/doc/scst_user_spec.txt
@@ -343,7 +343,7 @@ struct scst_user_scsi_cmd_parse
 	uint64_t sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	uint32_t timeout;
@@ -426,7 +426,7 @@ struct scst_user_scsi_cmd_alloc_mem
 	uint64_t sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	int32_t alloc_len;
@@ -535,7 +535,7 @@ struct scst_user_scsi_cmd_exec
 	uint64_t sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	int32_t data_len;
diff --git a/scst/include/scst.h b/scst/include/scst.h
index 405e816b4..59a7109bc 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -1240,7 +1240,7 @@ struct scst_cmd {
 
 	/* CDB and its len */
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	unsigned short cdb_len;
+	short cdb_len; /* it might be -1 */
 	unsigned short ext_cdb_len;
 	uint8_t *ext_cdb;
 
diff --git a/scst/include/scst_user.h b/scst/include/scst_user.h
index e3348bd3c..e53047d35 100644
--- a/scst/include/scst_user.h
+++ b/scst/include/scst_user.h
@@ -110,7 +110,7 @@ struct scst_user_scsi_cmd_parse {
 	aligned_u64 sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	int32_t timeout;
@@ -131,7 +131,7 @@ struct scst_user_scsi_cmd_alloc_mem {
 	aligned_u64 sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	int32_t alloc_len;
@@ -146,7 +146,7 @@ struct scst_user_scsi_cmd_exec {
 	aligned_u64 sess_h;
 
 	uint8_t cdb[SCST_MAX_CDB_SIZE];
-	uint16_t cdb_len;
+	int16_t cdb_len;
 	uint16_t ext_cdb_len;
 
 	int32_t data_len;
diff --git a/scst/src/scst_cdbprobe.h b/scst/src/scst_cdbprobe.h
index bdc74e60f..39034c13c 100644
--- a/scst/src/scst_cdbprobe.h
+++ b/scst/src/scst_cdbprobe.h
@@ -35,6 +35,7 @@ static int get_trans_len_serv_act_in(struct scst_cmd *cmd, uint8_t off);
 static int get_trans_len_single(struct scst_cmd *cmd, uint8_t off);
 static int get_trans_len_none(struct scst_cmd *cmd, uint8_t off);
 static int get_trans_len_read_pos(struct scst_cmd *cmd, uint8_t off);
+static int get_trans_cdb_len_10(struct scst_cmd *cmd, uint8_t off);
 
 /*
 +=====================================-============-======-
@@ -284,6 +285,8 @@ static const struct scst_sdbops scst_scsi_op_table[] = {
 	 SCST_DATA_NONE, FLAG_NONE, 0, get_trans_len_none},
 	{0x37, "O      O        ", "READ DEFECT DATA(10)",
 	 SCST_DATA_READ, FLAG_NONE, 8, get_trans_len_1},
+	{0x37, "        O       ", "INIT ELEMENT STATUS WRANGE",
+	 SCST_DATA_NONE, SCST_LONG_TIMEOUT, 0, get_trans_len_none},
 	{0x38, "    O  O        ", "MEDIUM SCAN",
 	 SCST_DATA_READ, FLAG_NONE, 8, get_trans_len_1},
 	{0x39, "OOOOOOOO        ", "COMPARE",
@@ -525,7 +528,7 @@ static const struct scst_sdbops scst_scsi_op_table[] = {
 	{0xBF, "            O   ", "VOLUME SET(OUT)",
 	 SCST_DATA_WRITE, FLAG_NONE, 6, get_trans_len_4},
 	{0xE7, "        V       ", "INIT ELEMENT STATUS WRANGE",
-	 SCST_DATA_NONE, SCST_LONG_TIMEOUT, 0, get_trans_len_none}
+	 SCST_DATA_NONE, SCST_LONG_TIMEOUT, 0, get_trans_cdb_len_10}
 };
 
 #define SCST_CDB_TBL_SIZE \
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index e517c071b..9f60168bd 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -2477,7 +2477,13 @@ int scst_get_cdb_len(const uint8_t *cdb)
 
 /* get_trans_len_x extract x bytes from cdb as length starting from off */
 
-/* for special commands */
+static int get_trans_cdb_len_10(struct scst_cmd *cmd, uint8_t off)
+{
+	cmd->cdb_len = 10;	
+	cmd->bufflen = 0;
+	return 0;
+}
+
 static int get_trans_len_block_limit(struct scst_cmd *cmd, uint8_t off)
 {
 	cmd->bufflen = 6;