Incomplete trace (due to high-speed SIM?)

Arthur Léna Lena at
Tue May 21 13:53:45 UTC 2013


I am trying to trace the communication between a Free Mobile (french 
operator) and an iPhone 4S. I am using the simtrace tool and libosmocore 
library taken from the Ubuntu PPA repository given in the user manual 
I tried booting the iPhone using 2 different SIMs (this one from Free 
Mobile and another one) and the trace seems very short using the Free 
Mobile in comparison to the other one. By parsing the ATRs of both SIMs, 
I found out that the communication is done at 312500 bits/s with the 
Free Mobile SIM and only 78125 bits/s (for a clock running at 5MHz). 
Could this explain the loss of entire ADPUs by the tracer? If yes, is 
there a way to remedy to this problem (firmware update for example).

Best regards,
Arthur Léna

FYI: the ATRS of both SIM cards
Free Mobile: 3B 9E 96 80 1F C7 80 31 E0 73 FE 21 1B 66 D0 01 77 97 0D 00 EC
TA(1) = 0x96 Fi=512, Di=32, 16 cycles/ETU (250000 bits/s at 4.00 MHz, 
312500 bits/s for fMax=5 MHz)

A1: 3B 3F 94 00 80 69 AF 03 0F 07 A4 00 00 06 0E 83 3E 9F 16
TA(1) = 0x94 Fi=512, Di=8, 64 cycles/ETU (62500 bits/s at 4.00 MHz, 
78125 bits/s for fMax=5 MHz)

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