I also think it's not a kernel issue since bluetoothctl is working and able to find Bluetooth low energy devices.
Bluez Ubuntu 18.04 version with latest focal kernel also results in: hcitool lescan Set scan parameters failed: Input/output error -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1870837 Title: hcitool lescan says 'Set scan parameters failed: Input/output error' To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/bluez/+bug/1870837/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
