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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 network adapters.

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 (WPA-PSK and WPA2-PSK). WPA is the current encryption standard for wireless networks. It is strongly recommended that WEP not be used as the sole mechanism to secure wireless communication, due to serious weaknesses in it. 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The firmware is outdated and contains known vulnerabilities.

July 15, 2018 OpenBSD-6.4