Firmware for reverse engineering b43?

[Jonas Gorski]

On Wed, Apr 15, 2026 at 1:44 PM Joshua Peisach <jpeisach at ubuntu.com> wrote:
>
> On Tue Apr 14, 2026 at 8:24 AM EDT, Jonas Gorski wrote:
> > On Tue, Apr 14, 2026 at 1:31 PM Joshua Peisach <jpeisach at ubuntu.com> wrote:
> >>
> >> On Tue Apr 14, 2026 at 5:14 AM EDT, Johannes Berg wrote:
> >> > I think there's no easy answer - what are you even trying to achieve?
> >> > Does b43 not work sufficiently well? Do you even know if some specific
> >> > calibration have a tendency to go out of whack? Is there later firmware
> >> > that has some advantage (given how little actually happens in firmware
> >> > in these devices, I'd be surprised by that) but isn't compatible with
> >> > the driver now, and you want to change that?
> >> >
> >> > I'd be tempted to say that if there's no problem there don't try to fix
> >> > anything, the hardware is ancient anyway, likely has few users, and
> >> > those users would probably be fine with just leaving it?
> >> >
> >> > johannes
> >>
> >> The BCM4321 (nphy) doesn't connect to my 5G network, so I figured that
> >> by filling in TODOs and FIXME's, I could eventually get something
> >> working.
> >>
> >> Other than that, I was thinking of making improvements for the sake of
> >> improving the driver.
> >
> > The initial version of the brcm80211 softmac driver [1] should also
> > help in making sense of some of the code (flag names etc). While it
> > officially only supports BCM43224 and newer on BCMA, it still had
> > remnants of support for older N-PHY revisions, so may help in finding
> > differences or explaining what code does.
> >
> > I once considered trying to clean up b43 based on brcmsmac, but never
> > got around to it.
>
> It does appear to be similar - even the current brcm80211. So much so
> that I sometimes need to think about whether b43 is actually a
> duplicated driver.
>
> Since b43 is in an orphan state, I thought it would be a great place to
> start for kernel development. 5G doesn't work on that iMac, some of the
> PHYs, like the AC PHYs appear to be incomplete - it felt reasonable.
>
> Because I'm one of those "there's always room for improvement people",
> I was going to try to improve the driver, filling out TODOs, fixing
> hardcoded register numbers, etc. But if it's best left alone.. then I
> guess we can do that.
>
> That is, assuming b43 is actually supposed to be a separate driver,
> because if brcmsmac basically has the same code, then maybe we should
> focus to centralizing everything? But then there's b43legacy.. hm...

It is/was intentionally a separate driver: Broadcom didn't want to
maintain support for obsolete chips (anything SSB, anything older than
BCM43224), so the decision was to have b43 support all the "legacy"
chips, while brcm80211 supports everything never. Since they were both
based on the same driver, they are (more or less) the same
architecture.

But now that Broadcom has essentially abandoned the softmac part of
brcm80211 since several years, I don't think there would be many
objections on unifying it with b43.

Best regards,
Jonas