On 06/07/2017 07:08 PM, João Paulo Rechi Vita wrote:
On Tue, Jun 6, 2017 at 6:41 PM, Larry Finger <larry.fin...@lwfinger.net> wrote:
On 06/06/2017 08:02 PM, João Paulo Rechi Vita wrote:
Hello b43 developers,
Is it possible to use b43-fwcutter to extract firmware from Windows
drivers? The manpage says "Currently b43-fwcutter supports Apple MacOS
X, Microsoft Windows and Linux drivers, but keep in mind that
b43-fwcutter doesn't support all driver versions.", but looking at
fwcutter_list.h I don't see entries for the windows drivers. Are
offsets for windows drivers available somewhere?
The reason that you do not see any entries for Windows drivers is because
those drivers are stripped such that we can get the offsets, but not the
description for that particular firmware entry. One could go through each
one and identify the correspondence with other firmware sources, but that
would be very laborious and error prone. I have chosen not to try that
approach.
What do you hope to gain from Windows firmware? Extracting firmware from the
Linux drivers should yield better firmware if the two operating systems have
different requirements.
Thanks for your reply, Larry.
The idea is to help non-techy users on dual-boot installations, when
they have no other means to connect their Linux system to the
internet. On Endless we support a very specific Windows+Endless
dual-boot layout, so it is easy for us to find the Windows partition.
We want grab the Windows drivers and extract the firmware files from
them automatically when a compatible card is detected and the user is
offline.
I understand that there is some manual work involved on this, but are
there any pointers on how to get the offsets from the Windows drivers?
I could check if the extracted data matches anything we already know
from the wl firmware.
Also, you mention that firmware may be different due to different OS
requirements -- I expected the hw (thus, also the firmware) to behave
the same way despite which OS is running on the CPU. Maybe I'm being
naive here?
In general, the firmware should be the same, but as I have not seen any
specifics on Windows drivers, there could be differences. The reverse
engineering started with MIPS drivers for Linux. We never looked at any RE for
Windows drivers.
A potential solution to your problem might be to use The method employed in
http://www.lwfinger.com/b43-firmware/no_net_install_bcm43xx_firmware.tar.bz2.
That tar file contains Broadcom object files with firmware for b43 and b43legacy
with a script that extracts the firmware files. It meets Broadcom restrictions
in that it only redistributes drivers, not firmware files. That particular tar
file contains 5.100.138 b43 firmware; however, it would be easy to package a
different driver, and adjust the extraction script accordingly. If it is not
possible to package the tar file as part of your Windows installation, at least
you could have your users download that file from a Windows boot, and then run
the firmware extraction from a Linux boot.
The only thing I ask is that you host the download on your server. I do not
promise to host those files in perpetuity. I wrote part of the script file, and
you have my permission to use it as you please as long as you preserve my
copyright. The rest of the script is part of the openSUSE package.
Larry
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