Comment 4 for bug 1433298

No change after BIOS update. (which seemed only a security release; not sure why you suspected that.)

 sudo dmidecode -s bios-version && sudo dmidecode -s bios-release-date
GCETA1WW (2.61 )
02/12/2015

I can't reproduce what happened in the past in more detail.
Here's what happens now:

After unplugging the external USB camera which I've now attached, running cheese gives stderr (/stdout):

$ cheese
libv4l2: error setting pixformat: Device or resource busy
libv4l2: error setting pixformat: Device or resource busy

(cheese:15898): cheese-WARNING **: Device '/dev/video1' is busy: gstv4l2object.c(2838): gst_v4l2_object_set_format (): /GstCameraBin:camerabin/GstWrapperCameraBinSrc:camera_source/GstBin:bin18/GstV4l2Src:video_source:
Call to S_FMT failed for YU12 @ 352x288: Device or resource busy

guvcview gives:

$ guvcview
V4L2_CORE: ERROR opening V4L interface: No such file or directory

lsusb gives:

$ lsusb
Bus 004 Device 003: ID 056a:00e6 Wacom Co., Ltd
Bus 004 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
Bus 004 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 003 Device 005: ID 04f2:b2ea Chicony Electronics Co., Ltd Integrated Camera [ThinkPad]
... etc