PNLM list overwritten

Dario Lombardo at
Fri Sep 7 21:12:45 UTC 2012

On Fri, Sep 7, 2012 at 6:02 PM, Brandon Creighton <cstone at> wrote:
> I've seen similar behavior before -- particularly trying to write
> EF.PLMNSEL, EF.FPLMN, and EF.{O,H,}PLMNwACT on some US-carrier SIMs.
> This seems to be worse in the ones from AT&T MVNOs (I've tried ones
> from Red Pocket and H2O).  Generally, the write just fails; but I
> believe I've observed some EFs get reset after a successful
> write/read.  Are you getting a valid response from the UPDATE BINARY
> command?

My software doesn't give me any error. Unplugging and replugging the
sim gives me good feedback: the test operator is still on the top of
the plnm.

> Unfortunately, I haven't found a reasonable workaround for this.  One
> ugly hack that seemed to work with some SIMs on an HTC One V (a recent
> Android phone ), is "priming" the SIM by first registering to the
> network using a old Nokia 3310 or similar; the connected data is
> stored on the SIM (EF.LOCI, I imagine?  I actually never figured out
> why this worked.) and is good for a one-time use in the smartphone.
> Writable or custom SIMs are reasonably inexpensive, so for anything
> over a handful of devices in a test network (with manual network
> selection), that's probably the way to go..

I tried to used expired sims because I have loads of them... :)

> Are you operating as MCC=001 MNC=01 (test network)?


> (Apologies to the list if this is the wrong venue for this.)
> On Fri, Sep 7, 2012 at 8:15 AM, Dario Lombardo
> < at> wrote:
>> Hil list
>> Today I've observed a strange behaviour when modifying the PNLM of
>> some real networks expired sims (to be used with osmocom and openbts).
>> I've put 001 01 on the top of the list. I've ejected and reinsterted
>> the sim in the reader many times, and I'm sure that the value has been
>> wrtitten.
>> When trying to connect to my test operator I get the message "your sim
>> card doesn't allow the connection to this network operator" from my
>> android phone.
>> Reading again the pnlm I see that the original list has been restored.
>> This astonishes me... Is is possible that the SIM overwrites the list
>> by itselt? Or is it the phone that does it? The android has an
>> original, not branded, operating system.
>> Thanks everybody for your help.
>> Dario

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