Newer MTK chipsets

[Mychaela Falconia]

Hello FreeCalypso community,

Someone just made a post to the OsmocomBB mailing list containing links
to a whole bunch of firmware source leaks for newer MTK chipsets which
supposedly support 3G/UMTS and 4G/LTE in addition to good old GSM/2G:

http://lists.osmocom.org/pipermail/baseband-devel/2017-April/005194.html

I personally am too heavily invested into the Calypso to even consider
looking at other chipsets, but as a community we do need to keep our
eyes somewhat open.  However, I currently absolutely lack the time to
take even a cursory look at any of the MTK source leaks linked above,
hence I am inviting other members of our community to take that look.

The basic question is: using these newer MTK source leaks, would it be
possible to build a libre modem board similar to our FCDEV3B, but with
support for 3G/UMTS and maybe even 4G/LTE in addition to GSM/2G?  Are
these MTK sources complete enough to actually rebuild a working modem
firmware image from them?  And what is the source vs. object mix
situation: do any of these leaks include real C source for the
dual-mode GSM+UMTS protocol stack and L1, or is it all in the form of
linkable binary objects/libs?

Another issue is the hardware platform.  It seems to me that the people
who are currently looking at the above-linked leaks and passing them
around are mostly hacking on Android phones, which is something I am
totally disinterested in.  If someone manages to replace or free the
baseband on an MTK Android phone, more power to them, but such a
project would be totally useless to me personally, as I principally
refuse to put an Android phone in my purse.  Instead the only kind of
phone I desire to have in my purse is a voice-only dumbphone.

Calypso is ideal for my needs, but the problem is that the uncaring
network operators are threatening to shut down their GSM/2G networks
because the total number of people in the world who actually desire
GSM/2G is fewer than 10, and the rest of the sheeple only want 4G+.
Thus my ideal voice-only dumbphone would support all of 2G, 3G and 4G,
but with an inverted network search preference order: always prefer 2G
networks when any 2G service is available, look for 3G networks only
when there is no 2G, and connect to 4G/LTE only as a last resort when
both 2G and 3G have been shut down - and when going into 4G/LTE mode,
use it *only* for VoLTE and not support any LTE Internet data services,
i.e., disable the latter as an act of protest against the mainstream
priorities.

In order to build something like the above, we would need a 3G/4G-capable
modem chip that is just a modem by itself (like what you would see
inside a USB stick modem product), as opposed to an AP+modem combo
made for running Android.  Hence we would need to find a non-AP-combo
modem chip from MTK (or Qualcomm MDMxxxx or whatever) with 3G/4G
capabilities for which we could build firmware from the available
leaked sources, *and* for which we can obtain sufficient hardware
documentation so we can build our own board like we did with FCDEV3B.

At this point I hand the above ideas over to the community.  On my end
I wish to fully finish the FCDEV3B project before I will take any look
at all at any of the newer chipsets, and it will probably be another
2-3 months to bring the FCDEV3B to a state which I would consider to
be fully complete.  But in the meantime, someone else can start
looking at possible candidates for a newer chipset.

Hasta la Victoria, Siempre,
Mychaela aka The Mother