Sorry for the long delay - when working on upstream kernel testing with
3.19.0-031900.201502091451 i386/32bit
to confirm bug 1422513 I realized that the internal Broadcom chip works fine after uninstalling
bcmwl-kernel-source and running with above kernel.

b43 seems to do fine in that case as lsmod indicates:

Module                  Size  Used by
nfnetlink_queue        17963  0 
nfnetlink_log          17665  0 
nfnetlink              14324  2 nfnetlink_log,nfnetlink_queue
ctr                    13025  1 
ccm                    17562  1 
dm_crypt               22836  1 
snd_hda_codec_realtek    68841  1 
snd_hda_codec_generic    63667  1 snd_hda_codec_realtek
snd_hda_intel          29576  3 
snd_hda_controller     30930  1 snd_hda_intel
snd_hda_codec         121018  4 snd_hda_codec_realtek,snd_hda_codec_generic,snd_hda_intel,snd_hda_controller
carl9170               86955  0 
snd_hwdep              13276  1 snd_hda_codec
uvcvideo               78147  0 
ath                    24509  1 carl9170
snd_pcm                89214  3 snd_hda_codec,snd_hda_intel,snd_hda_controller
videobuf2_vmalloc      13485  1 uvcvideo
videobuf2_memops       13170  1 videobuf2_vmalloc
videobuf2_core         45571  1 uvcvideo
arc4                   12509  2 
snd_seq_midi           13324  0 
snd_seq_midi_event     14475  1 snd_seq_midi
v4l2_common            14442  1 videobuf2_core
snd_rawmidi            25786  1 snd_seq_midi
videodev              140634  3 uvcvideo,v4l2_common,videobuf2_core
b43                   404250  0 
snd_seq                56978  2 snd_seq_midi_event,snd_seq_midi
bcma                   47124  1 b43
coretemp               13358  0 
snd_seq_device         14451  3 snd_seq,snd_rawmidi,snd_seq_midi
mac80211              643092  2 b43,carl9170
snd_timer              29036  2 snd_pcm,snd_seq
media                  21127  2 uvcvideo,videodev
joydev                 17311  0 
serio_raw              13251  0 
snd                    67102  16 snd_hda_codec_realtek,snd_hwdep,snd_timer,snd_pcm,snd_seq,snd_rawmidi,snd_hda_codec_generic,snd_hda_codec,snd_hda_intel,snd_seq_device
lpc_ich                17000  0 
cfg80211              462008  4 b43,ath,mac80211,carl9170
rfcomm                 59314  8 
btusb                  31907  0 
bnep                   19107  2 
bluetooth             444619  22 bnep,btusb,rfcomm
soundcore              14635  2 snd,snd_hda_codec
shpchp                 32280  0 
ideapad_laptop         18132  0 
sparse_keymap          13658  1 ideapad_laptop
mac_hid                13099  0 
parport_pc             32154  0 
ppdev                  17423  0 
lp                     13359  0 
parport                40945  3 lp,ppdev,parport_pc
ums_realtek            18008  0 
uas                    22257  0 
usb_storage            57197  2 uas,ums_realtek
i915                  956578  3 
i2c_algo_bit           13316  1 i915
drm_kms_helper        106489  1 i915
tg3                   159805  0 
psmouse               106642  0 
drm                   276577  5 i915,drm_kms_helper
ptp                    18938  1 tg3
pps_core               18768  1 ptp
pata_acpi              12901  0 
ssb                    56722  1 b43
video                  20019  1 i915
wmi                    18843  0