wifi not working... driver issues

Question

I'm trying to run Lubuntu 14.04 from a USB boot disk but not getting any wireless network access. I've looked through this forum and it seems to be a fairly common issue but haven't been able to find a fix that works for me.

Edit:

Further diagnostic info as requested: lubuntu@lubuntu:~$ lspci -knn | grep Net -A2 03:00.0 Network controller [0280]: Broadcom Corporation BCM4312 802.11b/g LP-PHY [14e4:4315] (rev 01) Subsystem: Foxconn International, Inc. T77H106.00 Wireless Half-size Mini PCIe Card [105b:e01b] Kernel driver in use: b43-pci-bridge

Edit: I ran the suggested fix Installing "firmware-b43-installer" offline and although it all seemed to run fine, it hasn't actually fixed the problem or changed the drivers being used.

Edit: I tried the Installing "firmware-b43-installer" offline fix again, this time using xubuntu, and now its working fine. Not sure why I couldn't get it to work with Lubuntu though. I guess I'll go with Xubuntu as my new OS instead.

Here's some diagnostic information:

lubuntu@lubuntu:~$ sudo lshw -class network
  *-network               
       description: Ethernet interface
       product: RTL8101E/RTL8102E PCI Express Fast Ethernet controller
       vendor: Realtek Semiconductor Co., Ltd.
       physical id: 0
       bus info: pci@0000:02:00.0
       logical name: eth0
       version: 02
       serial: 00:26:9e:29:2e:be
       size: 10Mbit/s
       capacity: 100Mbit/s
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress msix vpd bus_master cap_list rom ethernet physical tp mii 10bt 10bt-fd 100bt 100bt-fd autonegotiation
       configuration: autonegotiation=on broadcast=yes driver=r8169 driverversion=2.3LK-NAPI duplex=half latency=0 link=no multicast=yes port=MII speed=10Mbit/s
       resources: irq:24 ioport:2000(size=256) memory:d0110000-d0110fff memory:d0100000-d010ffff memory:d0120000-d012ffff
  *-network
       description: Network controller
       product: BCM4312 802.11b/g LP-PHY
       vendor: Broadcom Corporation
       physical id: 0
       bus info: pci@0000:03:00.0
       version: 01
       width: 64 bits
       clock: 33MHz
       capabilities: pm msi pciexpress bus_master cap_list
       configuration: driver=b43-pci-bridge latency=0
       resources: irq:17 memory:d0000000-d0003fff


lubuntu@lubuntu:~$ lspci
00:00.0 Host bridge: Intel Corporation System Controller Hub (SCH Poulsbo) (rev 07)
00:02.0 VGA compatible controller: Intel Corporation System Controller Hub (SCH Poulsbo) Graphics Controller (rev 07)
00:1b.0 Audio device: Intel Corporation System Controller Hub (SCH Poulsbo) HD Audio Controller (rev 07)
00:1c.0 PCI bridge: Intel Corporation System Controller Hub (SCH Poulsbo) PCI Express Port 1 (rev 07)
00:1c.1 PCI bridge: Intel Corporation System Controller Hub (SCH Poulsbo) PCI Express Port 2 (rev 07)
00:1d.0 USB controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #1 (rev 07)
00:1d.1 USB controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #2 (rev 07)
00:1d.2 USB controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB UHCI #3 (rev 07)
00:1d.7 USB controller: Intel Corporation System Controller Hub (SCH Poulsbo) USB EHCI #1 (rev 07)
00:1f.0 ISA bridge: Intel Corporation System Controller Hub (SCH Poulsbo) LPC Bridge (rev 07)
00:1f.1 IDE interface: Intel Corporation System Controller Hub (SCH Poulsbo) IDE Controller (rev 07)
02:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8101E/RTL8102E PCI Express Fast Ethernet controller (rev 02)
03:00.0 Network controller: Broadcom Corporation BCM4312 802.11b/g LP-PHY (rev 01)



lubuntu@lubuntu:~$ rfkill list all
0: hci0: Bluetooth
    Soft blocked: no
    Hard blocked: no
1: acer-wireless: Wireless LAN
    Soft blocked: no
    Hard blocked: no
2: acer-bluetooth: Bluetooth
    Soft blocked: no
    Hard blocked: no



lubuntu@lubuntu:~$ dmesg | grep -i firmware
[    0.160168] [Firmware Bug]: ACPI: BIOS _OSI(Linux) query ignored
[   15.016381] [Firmware Bug]: battery: (dis)charge rate invalid.
[   69.270176] b43 ssb0:0: Direct firmware load for b43/ucode15.fw failed with error -2
[   69.270265] b43 ssb0:0: Direct firmware load for b43/ucode15.fw failed with error -2
[   69.270386] b43 ssb0:0: Direct firmware load for b43-open/ucode15.fw failed with error -2
[   69.270450] b43 ssb0:0: Direct firmware load for b43-open/ucode15.fw failed with error -2
[   69.270466] b43-phy0 ERROR: Firmware file "b43/ucode15.fw" not found
[   69.270477] b43-phy0 ERROR: Firmware file "b43-open/ucode15.fw" not found
[   69.270487] b43-phy0 ERROR: You must go to http://wireless.kernel.org/en/users/Drivers/b43#devicefirmware and download the correct firmware for this driver version. Please carefully read all instructions on this website.

When I go to Preferences/additional drivers on the start menu I see:

Broadcom Corporation: T77H106.00 Wireless Half-size Mini PCIe Card This device is not working

It gives me the option of using Broadcom 802.11 Linux STA wiresless driver source from bcmwl-kernel-source (proprietary)

If I select that option and apply changes, after some minutes of apparently applying those changes the same dialogue box appears with the Do not use the device option checked again. That is, it doesn't seem to apply the proprietary driver.

I have no option of using an ethernet connection so please bear this in mind when suggesting a fix. I've seen several suggestions about downloading the drivers on a different machine and then running them from the lubuntu bootable usb but the recommended driver package (b43-fwcutter) is itself trying to connect and download other things, as far as I can tell. Also, this is the first time I've used linux so please give it to me in baby steps. Thanks.