Need to match driver to microcode?

Rafał Miłecki zajec5 at
Thu Feb 6 03:47:56 EST 2014

2014-02-06 9:19 GMT+01:00 grarpamp <grarpamp at>:
> On Thu, Feb 6, 2014 at 1:10 AM, Rafał Miłecki <zajec5 at> wrote:
>>> How does something like ' (r366174)' on the wrapper
>>> relate to its corresponding internal '784.2'? What are those
>>> strings each describing?
>> Broadcom's closed source driver embeds firmware in the driver. They
>> don't request it from the user space (ex. from /lib/firmware/).
>> However they develop driver and firmware independently, so they use
>> different numbering for them.
>> You can't really say what firmware version is embedded in the driver
>> until you load this firmware to the WiFi card and read the version
>> back.
>> What we do is downloading closed source driver (that was compiled for
>> some completely different system/architecture) and extract firmware
>> from it (which is a tiny part of the total size). We extract it to the
>> /lib/firmware/ and then b43 can use it.
> I should say i understand Broadcom makes a closed source
> linux driver:
> which I don't think includes the card firmware, but I'll
> try to unpack it again and look closer. Even if it does
> i don't see any reference on b43 site to fw ever being
> cut out of it and used with b43/insmod, only to blobs
> from GPL being used that way.

It has to include firmware, it's just (as I said) compiled into the binary.

We don't extract firmware from Linux STA because it wasn't available
for a long time, it was only recently updated and you can usually find
newer firmware in routers (MIPS/ARM) drivers.

> What I didn't understand was if I run strings on wl_apsta.o
> I get the first number, and b43 prints the second number
> when loading the firmware. I didn't get what those different
> numbers in the same .o/.fw file represented. And I'm
> not sure if the first number is present in the loaded firmware
> to also be printed on load.

I told you. The other number (784.2, etc.) is what firmware reports.
You have to upload firmware to the WiFi card and read it back. Since
the whole firmware in a blob (embedded in the driver), above number
(784.2) isn't visible as a string.

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