-  PrintAndLog("Sending data, please wait...");
-  for (i = 0; i < GraphTraceLen; i += 48) {
+  PrintAndLog("Sending [%d bytes]", GraphTraceLen);
+  for (i = 0; i < GraphTraceLen; i += USB_CMD_DATA_SIZE) {
     UsbCommand c={CMD_DOWNLOADED_SIM_SAMPLES_125K, {i, 0, 0}};
     int j;
     UsbCommand c={CMD_DOWNLOADED_SIM_SAMPLES_125K, {i, 0, 0}};
     int j;
       c.d.asBytes[j] = GraphBuffer[i+j];
     }
     SendCommand(&c);
     WaitForResponse(CMD_ACK,NULL);
       c.d.asBytes[j] = GraphBuffer[i+j];
     }
     SendCommand(&c);
     WaitForResponse(CMD_ACK,NULL);
   PrintAndLog("Starting simulator...");
   UsbCommand c = {CMD_SIMULATE_TAG_125K, {GraphTraceLen, gap, 0}};
   SendCommand(&c);
   PrintAndLog("Starting simulator...");
   UsbCommand c = {CMD_SIMULATE_TAG_125K, {GraphTraceLen, gap, 0}};
   SendCommand(&c);