Comment 14 for bug 1408963

I found this page because I am seeing the same problem in kubuntu 15.04 Vivid on a Lenovo Thinkpad T60 laptop.
The KDE5 plasma-nm (network manager) widget displays "connected" but all network connections are terminated.
When selecting "disconnect" in an attempt to reconnect, all wireless networks disappear from the listing.

Wired network continues to work but the systems slows way down.
Upon reboot, inspecting the first terminal shows that the system gets spammed with the

Apr 30 16:04:10 ********* kernel: [16419.742263] iwl3945 0000:03:00.0: Unable to set up bootstrap uCode: -5

error message as listed above.

I speak German but have not yet worked through the link
http://forum.ubuntuusers.de/topic/iwlwifi-streckt-die-fluegel-nach-wlan0-failed-/
I guess that's what I'll do next. Upon first inspection, this only seems to provide a temporary workaround rather than a fix.

Any help / instructions / workarounds / bug fixes to the kernel/firmware would be greatly appreciated.