How much protection does an add-on GSM modem give me vs. built into phone ?

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Denis 'GNUtoo' Carikli gnutoo at
Thu Oct 4 10:26:02 UTC 2012

On Thu, 4 Oct 2012 00:32:48 +0200
Peter Stuge <peter at> wrote:

> John Case wrote:
> > the real trick I am interested is isolating (or at least 
> > controlling) the interaction between the baseband processor and the 
> > application processor.  Using a computer with a USB dongle gives me
> > that control ... would I have that same level of control if we had
> > free software running on the baseband processor, or is there still
> > additional bleeding possible simpy by virtue of being built into
> > the computer ?
> In a smartphone it's almost not possible to distinguish the
> "computer" from the "GSM modem" anymore, because of how the
> hardware is constructed, so yes.
In some yes, in some no... it depend on how the smartphone was

On one end some smartphones (openmoko GTA02,golden delicious GTA04), the
baseband is isolated(tough on GTA04 it has access to a GPS with no
antenna(so it can't work)) . And on the other end there are smartphones
with qualcomm System on a chip...where the modem and the CPU are in a
single chip:
The modem part has the audio DSP connected to it, the GPS.
And the baseband uses shared RAM memory and shared NAND(if I remember
And I'm not sure but maybe the baseband is even needed for booting the
main CPU...

There are also systems in between like the galaxy S/Neuxs S that uses
shared memory but do not have other problems...


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