Detached command for DFU put the dongle in unknown state.

[dbelair]

Steps to reproduce

1. Build the 2018-12-R1 version for ARM
2. Install the tools an lib
3. Upload the new firmware with the -r argument

Expected behaviour

When the DFU finish, the tool will detach from this mode and the dongle will reconnect to the system normally.

Actual behaviour

The command always success to flash and detach but half the time the dongle is in an unknown state and don't reconnect to the system. The only way to be able to use it after is to unplug and plug it in. This isn't an accepted behaviour when we don't have direct access to the device to be unplugged or power cycled.

This is the LED state when that happen:
RSTLED = ON(green)
USBLED = ON(red)
1V8LED = ON(green)
TXLED = OFF
RXLED = OFF
USRLED = OFF

Version information

Operating system:
Debian 9 (stretch) on ARM

Ubertooth tools version (ubertooth-rx -V):
libubertooth 1.1 (git-0adf33e) => build from 2018-12-R1

libbtbb version:
libbtbb 1.0 (git-9d66440) => build from 2018-12-R1

Ubertooth firmware version (ubertooth-util -v):
Firmware version: git-0adf33e (API:1.06) => build from 2018-12-R1

Output

user@user:~$ sudo ubertooth-dfu -r -d bluetooth_rxtx.dfu
Switching to DFU mode...
Checking firmware signature
........................................
........................................
........................................
.
Detached
user@user:~$ sudo ubertooth-util -v
could not open Ubertooth device
ubertooth-util - command line utility for Ubertooth Zero and Ubertooth One

[mikeryan]

Known issue, cause unclear. I don't have a system on which I can reproduce this behavior reliably.