NetBSD firmware loader for Broadcom chip based Bluetooth adaptors
Modern Broadcom chips find their initial firmware instructions from an internal PROM after power up. This initial firmware is usually enough for proper functionality but, once running, bcmfw can upgrade it over the HCI interface with "Patch RAM" data files provided by Broadcom. bcmfw probes all adaptors connected to the Bluetooth protocol stack unless any are specified on the commandline, in which case only those are probed. The probe first checks the Manufacturer code with the standard "Read Local Version" command, and only when it is 15 (Broadcom) does it attempt to check the device itself, with vendor-specific commands.
Because the device will need to be reset afterwards, and to prevent errors in a running system, no update will be attempted unless bcmfw found the device in a non-enabled state.
Older BCM2033 based devices do not have firmware and will not initially be configured as Bluetooth adaptors, so will attach as ugen(4). If a ugen device name is passed on the commandline, bcmfw checks the USB Vendor & Product ID's directly before proceeding, which should be 0x0a5c and 0x2033 respectively.
The Patch RAM files are not available directly from Broadcom but since Feb 2017 are supplied via the Microsoft Windows Update Service and can be found at:
https://www.catalog.update.microsoft.com/Search.aspx?q=Broadcom+Bluetooth
The latest version available at this time is 12.0.1.1012, download this .cab archive, and extract to a temporary directory. There should be many ".hex" files and an ".inf" file, and the bcmfw-install program can be used to install firmware files and an index to your NetBSD filesystem.
After a successful update, the HCI revision of the device will change.