bluetooth not functional on nanopc-t4 at version 2.46.1+rev1

The device is rfkill blocked
Even after `rfkill unblock 0` we get:
> [  339.100838] [BT_RFKILL]: ENABLE UART_RTS
[  339.202018] [BT_RFKILL]: DISABLE UART_RTS
[  339.202534] [BT_RFKILL]: bt turn on power

but the bluetooth interface is still not available