diff --git a/doc/scst_user_spec.txt b/doc/scst_user_spec.txt
index 205de39fe..6eae9432c 100644
--- a/doc/scst_user_spec.txt
+++ b/doc/scst_user_spec.txt
@@ -336,7 +336,7 @@ 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;
@@ -415,7 +415,7 @@ 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;
@@ -524,7 +524,7 @@ 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 555ea9c39..5978d10e5 100644
--- a/scst/include/scst.h
+++ b/scst/include/scst.h
@@ -1235,7 +1235,7 @@ 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 76391bc50..e0ff97c30 100644
--- a/scst/include/scst_user.h
+++ b/scst/include/scst_user.h
@@ -108,7 +108,7 @@ 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;
@@ -128,7 +128,7 @@ 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;
@@ -143,7 +143,7 @@ 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 dc9ca6006..990943407 100644
--- a/scst/src/scst_cdbprobe.h
+++ b/scst/src/scst_cdbprobe.h
@@ -34,6 +34,7 @@ static int get_trans_len_read_capacity(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);
 
 /*
 +=====================================-============-======-
@@ -271,6 +272,8 @@ 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",
@@ -502,7 +505,7 @@ 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}
 };
 
 /* Notes:
diff --git a/scst/src/scst_lib.c b/scst/src/scst_lib.c
index fdea446e4..2014eb3b4 100644
--- a/scst/src/scst_lib.c
+++ b/scst/src/scst_lib.c
@@ -2432,7 +2432,13 @@ 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;