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BWFM(4) Device Drivers Manual BWFM(4)

bwfmBroadcom and Cypress IEEE 802.11a/ac/b/g/n wireless network device

bwfm* at pci?
bwfm* at sdmmc?
bwfm* at usb?

The bwfm driver provides support for Broadcom and Cypress FullMAC wireless network adapters.

The following table summarizes supported chipsets and their capabilites, as well as the bus attachments recognized by the bwfm driver:

BCM43143 2GHz 1x1 SDMMC/USB
BCM43236 2GHz/5GHz 2x2 USB
BCM4324 2GHz/5GHz 2x2 SDMMC
BCM43242 2GHz/5GHz 2x2 USB
BCM4329 2GHz/5GHz 2x2 SDMMC
BCM4330 2GHz/5GHz 2x2 SDMMC
BCM4334 2GHz/5GHz 2x2 SDMMC
BCM43340 2GHz/5GHz 1x1 SDMMC
BCM43341 2GHz/5GHz 1x1 SDMMC
BCM4335 2GHz/5GHz 1x1 SDMMC
BCM43362 2GHz 1x1 SDMMC
BCM43364 2GHz 1x1 SDMMC
BCM4339 2GHz/5GHz 1x1 SDMMC
BCM43430 2GHz 1x1 SDMMC
BCM43455 2GHz/5GHz 1x1 SDMMC
BCM43456 2GHz/5GHz 2x2 SDMMC
BCM4350 2GHz/5GHz 2x2 PCI
BCM4354 2GHz/5GHz 2x2 SDMMC
BCM4356 2GHz/5GHz 2x2 PCI/SDMMC
BCM43569 2GHz/5GHz 2x2 USB
BCM43602 2GHz/5GHz 3x3 PCI
BCM4371 2GHz/5GHz 2x2 PCI

These are the modes the bwfm driver can operate in:

BSS mode
Also known as mode, this is used when associating with an access point, through which all traffic passes. This mode is the default.
Host AP
In this mode the driver acts as an access point (base station) for other cards.

The bwfm driver can be configured to use Wired Equivalent Privacy (WEP) or Wi-Fi Protected Access (WPA1 and WPA2). WPA2 is the current encryption standard for wireless networks. It is strongly recommended that neither WEP nor WPA1 are used as the sole mechanism to secure wireless communication, due to serious weaknesses. WPA1 is disabled by default and may be enabled using the option "wpaprotos wpa1,wpa2". For standard WPA networks which use pre-shared keys (PSK), keys are configured using the "wpakey" option. WPA-Enterprise networks require use of the wpa_supplicant package. The bwfm driver relies on the software 802.11 stack for the WPA handshake. Both encryption and decryption of data frames are handled by the firmware.

The firmware automatically selects the transmit speed and the channel depending on the received signal strength.

The bwfm driver can be configured at runtime with ifconfig(8) or on boot with hostname.if(5).

The driver needs a firmware file which is loaded when the driver attaches. A prepackaged version of the firmware can be installed using fw_update(1).

The following example scans for available networks:

# ifconfig bwfm0 scan

The following hostname.if(5) example configures bwfm0 to join network “mynwid”, using WPA key “mywpakey”, obtaining an IP address using DHCP:

nwid mynwid wpakey mywpakey

The following hostname.if(5) example creates a host-based access point on boot:

mediaopt hostap
nwid mynwid wpakey mywpakey

arp(4), ifmedia(4), intro(4), netintro(4), pci(4), usb(4), hostname.if(5), ifconfig(8)

The bwfm driver first appeared in OpenBSD 6.3.

The bwfm driver was written by Patrick Wildt <>.

The firmware is outdated and contains known vulnerabilities.

This driver does not support powersave mode.

April 20, 2020 OpenBSD-6.7