QUESTION: Hacking WIFI card firmware possible?

[Timothy C Holtom]

I have the following question:

Is it possible to modify the firmware of a wifi card? The reason I
ask is that
given that a wifi card is essentially a spread spectrum tranceiver,
and given that the frequency, power and many other RF characteristics
on RF chips are software programmable, could I essentially design my
own SS tranceiver if only I knew the chips used, and the firmware
upgrade mechanism?

I suspect the answer to this question is yes and no: Yes you can
upgrade the firmware of some wifi cards, by re-writing the eeprom, but
the characteristics of the trancseiver/DSP chip are not modifyable.

 

[Ian Stirling]

Timothy C Holtom <Timothy@tholtom.freeserve.co.uk> wrote:

I have the following question:

Is it possible to modify the firmware of a wifi card? The reason I
ask is that
given that a wifi card is essentially a spread spectrum tranceiver,
and given that the frequency, power and many other RF characteristics
on RF chips are software programmable, could I essentially design my
own SS tranceiver if only I knew the chips used, and the firmware
upgrade mechanism?

I suspect the answer to this question is yes and no: Yes you can
upgrade the firmware of some wifi cards, by re-writing the eeprom, but
the characteristics of the trancseiver/DSP chip are not modifyable.

Most of the 802.11 protocol is done in software in many cards.
In some cards this will be reloadable.
However, in most cases the tranciever is a block of logic, and not
upgradable.
This does things like spreading and unspreading the signal, ...
So, you are probably limited to 802.11 -like networks.

I looked at this briefly, as it would have been interesting to me to
look at very low bitrates.
For example, at 1mbps 802.11b uses an 11 bit chip length spreading
code.
If you upped this to 11000 bits, you'd get 1000bits/second, and
around 30 times the range.
However, I doubt that this is possible with any chipsets.