%XSIM: 0,9 error - nrf9160 is not detecting the sim-cards

[Oleh Hordiichuk]

Hello,

we are facing sim card detection issue with nrf9160 dev-kit. This is the same issue as described here: nrf9160 - SIM communication problem - Ooredoo SIM . Multiple sim cards we have from one operator are working, and multiple sim cards from different operator are not working at all returning %XSIM: 0,9 error.

Based on suggestions we found on this forum we decided to check if the non-working sim cards are supporting 1.8V. So we took simcom7080g modem, which also supports only 1.8V sim-cards and checked with it - everything is working properly and the sim-card is detected and capable to successfully register to the network.

We have also contacted operator to confirm - they cannot say precisely whether the sim cards have 1.8V support, but they should have support and suggested us to send a new batch of sim cards, which we have ordered and checked with same negative result. But since simcom7080g is capable to work with them, we assume they have 1.8v support. So even sim cards from 2 different batches from the same operator are not working.

Additionally we have checked voltage supply to sim cards. For working sim-cards nrf9160 provides and holds voltage. For non-working nrf9160 provides voltage for short period of time and then disables it. So we assume this is related to initialisation procedure of the sim card. So we decided to install nrf9160dk_serial_lte_modem_debug_2023-06-01_0677b099.hex firmware and check logs from RTT, unfortunately there are no useful logs (errors):

00> *** Booting Zephyr OS build v3.3.99-ncs1 ***

00> [00:00:00.496,917] <inf> nrf_modem_lib_trace: Trace thread ready

00> [00:00:00.498,352] <inf> nrf_modem_lib_trace: Trace level override: 2

00> [00:00:00.498,352] <inf> slm: Serial LTE Modem

00> [00:00:00.498,382] <inf> slm_at_host: UART0 baud: 115200 d/p/s-bits: 3/0/1 HWFC: 0

00> [00:00:00.599,548] <inf> slm_at_host: at_host init done

We have also noticed that working and non-working sim-cards are different in terms of pins area. Not sure it impacts somehow, but please see the picture:

To sum it up, we assume this is not related to 1.8V, but to sim card initialisation procedure. Please help to overcome this issue because this is the only operator in the country, which is supporting NB-IoT and we can't launch the solution.

[Didrik Rokhaug]

Hi,

Can you take a modem trace, so that we can see what the modem is doing when it tries to initialize the SIM card?

Best regards,

Didrik

[Oleh Hordiichuk]

Hello Didrik,

please see the traces: https://drive.google.com/file/d/1Rkgjg2MLkYDBYgo7j0XfPpWeQNIuCyS1/view?usp=sharing

Kind regards,

Oleh

3348.trace.zip

[Didrik Rokhaug]

Thanks.

I've asked the modem team to take a look at the traces. However, due to summer vacations, it might take longer than usual to get a reply from them.

[Oleh Hordiichuk]

Thank you! Looking forward to a reply.

Additionally, we have checked the voltage supplied to the sim card from simcom modem and it's 1.8V. So we can confirm the sim cards are supporting 1.8V.

[Didrik Rokhaug]

Hi, and sorry for this taking some time.

I got an answer from the modem team:

"The problem is in validity check of EF_AD (one of the files on the SIM card), i.e. the EF_AD on the SIM card is considered invalid by our SW. According to log file, content of the EF_AD is '00ffff' that does not meet the requirements specified in 3GPP TS 31.102:

According to the modem trace, the content of the EF_AD is '00ffff'. The 4th byte, “length of MNC in the IMSI“, is missing.

Or, perhaps it would be more correct to say, that the EF_AD is according to old version of standard, that is not supported by our current v1.3 modem SW. The missing “length of MNC in IMSI“ field has been added to the USIM specification 3GPP TS 31.102 in V3.2.0 (2000-07), and in earlier SIM specification (3GPP TS 51.011) it has been an optional field. Our modem SW implementation is based mostly on 3GPP TS 31.102 V13.0.0 and later."