Can't create Ad-Hoc WiFi connection

[Petr]

I'm trying to create Ad-Hoc WiFi connection from BQ Aquaris M10 Ubuntu Edition to Nokia N900, running Qt Mobile Hotspot.
My desktop PC connects ok, but Ubuntu Touch can't connect with message:
wlan0: Association request to the driver failed

I've tried unpotected and WEP protected connection.

As a consequence to this failure, tablet reboots when next time connecting to normal infrastructure AP.

ProblemType: Bug
DistroRelease: Ubuntu 15.04
Package: wpasupplicant 2.4-0ubuntu7~overlay3
Uname: Linux 3.10.93+ aarch64
ApportVersion: 2.17.2-0ubuntu1.3touch1
Architecture: armhf
Date: Sat Jun 11 18:49:04 2016
InstallationDate: Installed on 2016-05-24 (18 days ago)
InstallationMedia: Ubuntu 15.04 - armhf (20160524-114757)
SourcePackage: wpa
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

[Expired for wpa (Ubuntu) because there has been no activity for 60 days.]