title: hcitool lescan does not work on Bluetooth version 5
body: <p>It has turned out to me that <code>hcitool</code> is not capable of running <code>lescan</code> on Bluetooth v5.X hardware. Running <code>sudo hcitool lescan</code> would result in this error: <code>Set scan parameters failed: Input/output error</code>.</p>
  <p>The community suggests to use <code>bluetoothctl</code> instead (e.g. <a href="https://stackoverflow.com/a/60322966/5185597">here</a>) but <code>gatttool</code> is dependent on <code>hcitool</code> for scanning ble devices. While <code>gatttool</code> serves as a ble backend on many apps, still no solution is provided to resolve the Input/output error mentioned above. Does anybody know how to resolve the above error?</p>
  <p>I have tested the full functionality of my BLE on Windows 10 but in Ubuntu I have failed so far. My laptop has the following bluetooth hardware:</p>
  <pre><code>$ hciconfig -a
  hci0:   Type: Primary  Bus: USB
      BD Address: 4C:1D:96:30:83:6E  ACL MTU: 1021:4  SCO MTU: 96:6
      UP RUNNING 
      RX bytes:8099 acl:34 sco:0 events:591 errors:0
      TX bytes:11990 acl:34 sco:0 commands:452 errors:0
      Features: 0xbf 0xfe 0x0f 0xfe 0xdb 0xff 0x7b 0x87
      Packet type: DM1 DM3 DM5 DH1 DH3 DH5 HV1 HV2 HV3 
      Link policy: RSWITCH SNIFF 
      Link mode: SLAVE ACCEPT 
      Name: 'xxxx'
      Class: 0x0c010c
      Service Classes: Rendering, Capturing
      Device Class: Computer, Laptop
      HCI Version: 5.1 (0xa)  Revision: 0x100
      LMP Version: 5.1 (0xa)  Subversion: 0x100
      Manufacturer: Intel Corp. (2)
  </code></pre>
  <p>I have Ubuntu 20.04 with bluez v5.53.</p>