Using GT-I9100 in USA

Michael Spacefalcon msokolov at ivan.Harhan.ORG
Wed Oct 2 22:13:24 UTC 2013

Nick <replicant at> wrote:

> It might be worth going into a T-Mobile shop and telling them your
> problem. [...]

The international SGS2 was *never* approved for use with T-Mobile USA
or with any other operator in this country.  Considering that it can
only ever work in 2G/EDGE mode, the only people who would ever even
consider using a phone of this kind in this country would have to be
GSM and/or Freedom religious zealots like me, and there aren't a whole
lot of such people.

Brian Kemp <brian.kemp at> wrote:

> It's not an amazing solution, but you can swap a mini-SIM for a
> micro-SIM for free, at least on AT&T.

Of course, the same with T-Mobile - but I would NOT want to be asking
them to change my SIM back and forth 5 times a day.  Being able to
move my SIMs back and forth among different phones (development/test)
is an absolute must for me, and I have standardized on the mini-SIM
form factor.

> My wife did it when she went
> from a Nexus S to a Nexus 4 (she has no interest in running Replicant,
> but I get her old phone.)

Are you using Replicant on a Nexus S successfully in USA?  Exactly
which model variant?  On AT&T or on T-Mobile?  2G/EDGE or 3G/UMTS/etc?

> Does your physical location change when you do this, or can you simply
> repeat it no matter where you are?

The latter.  At least if the "no matter where you are" part is confined
to Southern California, the "normal" parts thereof with regular cell
coverage - I have not tried flying overseas just to test this phone in
another country, nor have I yet found a Faraday cage to test how the
phone would behave in the absence of any external RF signals.

> Wondering if two towers are
> 'fighting' for registration of your phone.

Everything is possible - it appears that some condition occurs in the
baseband fw that causes it to go into a tizzy.  What the bug-tickling
condition is, I have no way of telling.

> There is something seriously wrong with this phone. I don't know if
> it's the model, or if a modem firmware upgrade will solve it, but that
> would be my first suggestion.

Because I'm trying to devote my time to something much more worthy in
the long run (see below), I am still hoping that someone would take me
up on my cash offer.  If there is anyone in USA who would be willing
to take a stab at getting this I9100 to work, I will gladly ship my
phone to that person, maybe even with a T-Mobile SIM card thrown in,
and if you can get it to work, I will gladly send you $$$.  (At least
$500, may be willing to negotiate higher.)

The "much more worthy in the long run" thing I'm working on is a 100%
OSHW (open source hardware) phone, running 100% Free Software
_*including the GSM modem*_.  You've all probably heard about the just
recently started Neo900 project, right?  (  That project
isn't mine, there are some other folks working on it, but I am working
on this special option for the upcoming Neo900:

Of course it is far too early to promise anything for certain, but I
do very much hope that this Neo900 project succeeds.  If these German
guys succeed in building the Neo900, and if the hw design makes it
possible to populate my FreeCalypso modem in place of the more
"standard" Option 3G/LTE/whatever module (I'm working with Joerg on
this one), it would make the whole thing a reality that much sooner.
If the Neo900FC idea fails for whatever reason, I would still produce
my FreeCalypso modem, but then I would have to partner up with someone
else to turn it into a complete phone: I am absolutely the wrong
person to design any part of a smartphone other than the GSM modem.
Once again, I very much hope the Neo900FC idea flies, as we've got
some good synergy going there.

But what brought me to Replicant is the need for some quick interim
solution for my significant other.  It is very important for me to get
her to use Free Software on her phone, and it needs to happen now,
without waiting for Neo900 or Neo900FC: I need my S.O. to be using
Free Software *now* in order to be in the right mental and emotional
state to do the FreeCalypso work.

Of the already-existing phones supported by Replicant, SGS3 would
probably be the best, but it has that nasty micro-SIM slot, and I've
almost convinced my S.O. that with Replicant on the device, she would
most likely see no difference at all between I9100 (S2) and I9300 (S3),
except for the I9300 being wider.  (She says she really wanted an S3
Mini, but I doubt that there is a version of that one supported by
Replicant - please correct me if I'm wrong, though.)  Hence I have set
it as my short-term goal to get that I9100 working here in USA, maybe
with "normal" sw first, and then later with Replicant.  (But if
jumping straight to Replicant would make it work reliably as a phone,
I'm game for that too.)

Hence I'm wondering if I can hire someone else to do the short-term
hackwork of getting a working phone for my S.O. while I focus my own
energy on the much-more-worthy-in-the-long-term Neo900 & FreeCalypso

At this point I would probably be happy with *any* Replicant
4.0-supported phone that will work here in USA, using T-Mobile USA in
EDGE mode.  But the I9100 aka SGS2-international (be it the physical
unit I have or another one, in case mine is physically defective)
would be ideal, as I've already made an emotional attachment to it,
and so has my S.O. - she played with it for a while and really liked
it, until she saw that crazy erratic network connection behavior.

Anyone who would like to take a stab at it, please send me your snail
mail address by unicast and my I9100 will be on its way to you.
Alternatively, if you already have an I9100 which you believe will
work with T-Mobile USA EDGE, and you wouldn't mind parting with it,
I'll buy it from you for $1000 USD - with a proviso that you would
need to be willing to take it back for a full refund if it exhibits
the same behavior as my current one does when it gets here and I put a
T-Mobile USA SIM card in it.  (My S.O. would need it to be black
though, I doubt I can convince her to use a white one.  Was the I9100
ever made in any other color besides black and white?)

> I wonder if it's trying to communicate on a frequency that the radio
> doesn't support.

Quite possible indeed: T-Mobile USA UMTS has downlink on 2100 MHz and
uplink on 1700 MHz.  "Standard" aka "international" 3G phones like
this I9100 (and probably many others) support 3G/UMTS on 2100 MHz, but
not 1700 MHz.  So if the phone has 3G enabled, it may hear UMTS signal
on 2100 MHz, try to register on that network, but the BTS will never
hear that transmission.  But I have this I9100 configured for
"GSM only" under "Mobile networks"...

> Install F-Droid and look for the "Network" application. You'll know
> it's the right one when it says it's merely a wrapper for something
> already in Android. Icon is white circle with black old land-line
> phone handset in it.

See above about not having the time to delve into it deeper myself.

> You *may* be able to use those settings to force the radio to not do
> stupid things - such as Preferred Network Type, etc. (My Nexus S lists
> "WCDMA preferred" which I'm assuming is a default.)

See above: I've already set mine to "GSM only".

> It used to be that international versions worked best on T-Mobile, and
> AT&T was the odd network out.

See my question at the beginning of this post regarding what you are
using / what works for you, and with what phone model.


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