Comment 92 for bug 1859592

I used to get the following error after each reboot. That started happening after the most recent Ubuntu 20.04 update.

Bluetooth: hci0: command 0xfc05 tx timeout
Bluetooth: hci0: Reading Intel version command failed (-110)

I verified that the following workaround works for me. Thankfully, it does not involve pulling out the power plug.

First verify that your device is reported as DOWN.

~ $ hciconfig
hci0: Type: Primary Bus: USB
 BD Address: 00:00:00:00:00:00 ACL MTU: 0:0 SCO MTU: 0:0
 DOWN
 RX bytes:0 acl:0 sco:0 events:0 errors:0
 TX bytes:4 acl:0 sco:0 commands:1 errors:0

If so, run the following command:

~ $ sudo hciconfig -a hci0 up

and then reboot normally. I was able to use Bluetooth normally after that step.