1: 00000001 03-0C 00                      HCI_Reset
  2: 00000002 0E 0B 01 05-10 00 36 01 40 0A Command_Complete HCI_Read_Buffer_Size
  3: 00000002 0E 04 01 03 0C 00             Command_Complete HCI_Reset

  4: 00000001 01-0C 08 FF FF FF FF FF FF FF HCI_Set_Event_Mask
  5: 00000002 0E 04 01 01 0C 00             Command_Complete

  6: 00000001 01-10 00                      HCI_Read_Local_Version_Information
  7: 00000002 0E 0C 01 01 10 00 06 86 1D 06 Command_Complete

  8: 00000001 02-10 00                      HCI_Read_Local_Supported_Commands
  9: 00000002 0E 44 01 02-10 00 FF FF FF 03 Command_Complete
 10: 00000002 FF FF F3 0F E8 FE 3F F7 83 FF 
 11: 00000002 FF FF 7F 00 00 00 00 00 00 00 
 12: 00000002 00 00 00 00 00 00 00 00 00 00 
 13: 00000002 00 00 00 00 00 00 00 00 00 00 

 14: 00000001 03-10 00                      HCI_Read_Local_Supported_Features
 15: 00000002 0E 0C 01 03-10 00 FF FF 8F FE Command_Complete

 16: 00000001 04-10 01 00                   HCI_Read_Local_Extended_Features
 17: 00000002 0E 0E 01 04-10 00 00 00 FF FF Command_Complete

 18: 00000001 05-10 00                      HCI_Read_Buffer_Size

どうしてもここで応答がなくなる。
evtバッファ長が16バイトだと、この現象が出るようだ。
大きくすると現象が出なくなる。