diff --git a/backend_hiti.c b/backend_hiti.c
index c71a499..740c1bc 100644
--- a/backend_hiti.c
+++ b/backend_hiti.c
@@ -48,16 +48,16 @@ struct hiti_cmd {
 #define CMD_STATUS_OK      0x50
 #define CMD_STATUS_OK2     0x51 /* Seen with ERDC_RLC on p51x */
 #define CMD_STATUS_OK3     0x53 /* Seen with EPC_SP on p51x, sometimes? */
-#define CMD_STATUS_BAD_CMD 0xd8 /* Seen with EFM_RD on p51x */
+#define CMD_STATUS_BAD_CMD 0xd8 /* eg seen with EFM_RD on p51x */
 #define CMD_STATUS_UNK2    0xdb /* Seen with ESD_SEHT2 on p51x */
 
 /* Request Device Characteristics */
 #define CMD_RDC_RS     0x0100 /* Request Summary */
-#define CMD_RDC_ROC    0x0104 /* Request Option Characteristics XX (1 resp) */
+#define CMD_RDC_ROC    0x0104 /* Request Option Characteristics XX (1 resp, not p51x) */
 
 /* Printer Configuratio Control */
 #define CMD_PCC_RP     0x0301 /* Reset Printer (1 arg) */
-#define CMD_PCC_STP    0x030F /* Set Target Printer (1 arg) XX -- master or slave perhaps? */
+#define CMD_PCC_STP    0x030F /* Set Target Printer (1 arg) XXX -- 00 == master or 01 == slave ? Or maybe it's a bank select for CMD_EFM_RNV? */
 
 /* Request Device Status */
 #define CMD_RDS_RSS    0x0400 /* Request Status Summary */
@@ -85,10 +85,11 @@ struct hiti_cmd {
 #define CMD_ERDC_RLC   0x8006 /* Request LED calibration */
 #define CMD_ERDC_RSN   0x8007 /* Read Serial Number (1 arg) */
 #define CMD_ERDC_C_RPCS 0x8008 /* CS Request Printer Correction Status */
+#define CMD_ERDC_CTV   0x8008 /* Color Table Version XXX p51x, string (14 byte reply?) */
 #define CMD_ERDC_RPIDM 0x8009 /* Request PID and Model Code */
 #define CMD_ERDC_RTLV  0x800E /* Request T/L Voltage */
 #define CMD_ERDC_RRVC  0x800F /* Read Ribbon Vendor Code */
-#define CMD_ERDC_UNK   0x8010 /* Unknown Query RE */
+#define CMD_ERDC_UNK1  0x8010 /* Unknown Query RE */
 #define CMD_ERDC_UNK2  0x8011 /* Unknown Query RE */
 #define CMD_ERDC_RHA   0x801C /* Read Highlight Adjustment (6 resp) RE */
 
@@ -132,8 +133,8 @@ struct hiti_cmd {
 #define CMD_ESD_C_SHPTC  0x830C /* CS Send Heating Parameters & Tone Curve XX (n arg) */
 
 /* Extended Flash/NVram */
-#define CMD_EFM_RNV    0x8405 /* Read NVRam (1 arg) XX */
-#define CMD_EFM_RD     0x8408 /* Read single location (2 arg) -- XXX RE not P51x */
+#define CMD_EFM_RNV    0x8405 /* Read NVRam (1 arg) -- arg is offset, 1 byte resp of data @ that offset. -- All newer than P51x */
+#define CMD_EFM_RD     0x8408 /* Read single location (2 byte offset arg, 1 byte of data @ that offset -- not P51x */
 #define CMD_EFM_SHA    0x840E /* Set Highlight Adjustment (5 arg) -- XXX RE */
 
 /* Extended Security Control */
@@ -465,6 +466,7 @@ static int hiti_query_job_qa(struct hiti_ctx *ctx, struct hiti_job *jobid, struc
 static int hiti_query_status(struct hiti_ctx *ctx, uint8_t *sts, uint32_t *err);
 static int hiti_query_version(struct hiti_ctx *ctx);
 static int hiti_query_matrix(struct hiti_ctx *ctx);
+static int hiti_query_matrix_51x(struct hiti_ctx *ctx);
 static int hiti_query_supplies(struct hiti_ctx *ctx);
 static int hiti_query_tphv(struct hiti_ctx *ctx);
 static int hiti_query_statistics(struct hiti_ctx *ctx);
@@ -869,11 +871,13 @@ static int hiti_get_info(struct hiti_ctx *ctx)
 	     ctx->erdc_rs.dpi_cols,
 	     ctx->erdc_rs.dpi_rows);
 
-	if (ctx->conn->type != P_HITI_51X) {
+	if (ctx->conn->type == P_HITI_51X) {
+		ret = hiti_query_matrix_51x(ctx);
+	} else {
 		ret = hiti_query_matrix(ctx);
-		if (ret)
-			return CUPS_BACKEND_FAILED;
 	}
+	if (ret)
+		return CUPS_BACKEND_FAILED;
 
 	uint32_t buf[2] = {0,0};
 	ret = hiti_query_counter(ctx, 1, buf, ctx->erdc_rpc_len);
@@ -891,7 +895,7 @@ static int hiti_get_info(struct hiti_ctx *ctx)
 		return CUPS_BACKEND_FAILED;
 	INFO("6x8 prints: %u\n", buf[0]);
 
-	if (ctx->conn->type != P_HITI_51X) {
+	{
 		int i;
 		DEBUG("MAT ");
 		for (i = 0 ; i < 256 ; i++) {
@@ -2562,6 +2566,22 @@ static int hiti_query_matrix(struct hiti_ctx *ctx)
 			return ret;
 	}
 
+	return CUPS_BACKEND_OK;
+}
+
+static int hiti_query_matrix_51x(struct hiti_ctx *ctx)
+{
+	int ret;
+	int i;
+	uint16_t len = 1;
+
+	for (i = 0 ; i < 256 ; i++) {
+		uint8_t offset = i;
+
+		ret = hiti_docmd_resp(ctx, CMD_EFM_RNV, (uint8_t*)&offset, sizeof(offset), &ctx->matrix[i], &len);
+		if (ret)
+			return ret;
+	}
 
 	return CUPS_BACKEND_OK;
 }
@@ -2721,7 +2741,7 @@ static const char *hiti_prefixes[] = {
 
 const struct dyesub_backend hiti_backend = {
 	.name = "HiTi Photo Printers",
-	.version = "0.44",
+	.version = "0.45",
 	.uri_prefixes = hiti_prefixes,
 	.cmdline_usage = hiti_cmdline,
 	.cmdline_arg = hiti_cmdline_arg,