nRF9160 fails to attach after several RESETs & attach without power cycle

[Michal Mühlpachr]

Hi,

nRF9160 with SLM NCS v1.9.1 fails to attach after 7th RESET (by RESET pin) & attach without power cycle.

There is not any ERROR state reported by modem, modem fails to attach forever without power cycle.

After nRF9160 power cycle it attaches immediately with same AT sequence.

We need reliable initialization of nRF9160 SLM/Modem without nRF9160 power cycle because we do not have load power in production HW - issue threatens device stability in the field.

I prepared Python script to reproduce issue with nRF9160DK, you can find it together with log at https://gist.github.com/muhlpachr/40a4d8f1b332aee8a25fa7e1ad023751
Modify COM port for AT commands according your PC setup please.

Issue is 100% reproducible.

Attached you can find modem trace.

Thank you.

Regards,
Michal

trace-2022-03-24T23-42-16.760Z.bin

[Michal Mühlpachr]

The reason why we are resetting nRF91 is development cycle.

In our HW nRF91 with SLM is controlled by host MCU nRF52. When nRF52 is flashed and new version of our application starts to execute, it needs to transit nRF9160/SLM in guaranteed known state at startup, so it resets nRF91 during startup by pin.

We suppose it is not wise to start nRF91 initialization by +CFUN=0 because:
1. it would store plenty of undefined configuration in nRF91 NVM
2. since nRF91 NVM is implemented in flash, it would wear nRF91 flash fast during app development and tests on nRF52 (e.g. application on nRF52 can be restarted by Zephyr shell command)

It is not feasible to power-cycle our HW during app development because there are supercaps and constant current power source to protect batteries (it operate from bench PSU during development but current limit circuity is active all the time even during development - is has to, to properly test HW+SW) and those discharge-charge supercaps cycle takes time.

We would take pain and wait 60+ seconds at application startup during development cycle but it does not help to prevent RESET LOOP protection because nRF91/SLM does not behave like it is described/supposed.

Comment/info from developers is not related to collected trace in any manner (there are 120+ seconds delays after modem initialization between RESETs on nRF91), it just describes how nRF91 is supposed to behave.

It is not the case unfortunately and it is obvious from trace, I do not know how to prove it more.
Why you can not see it from trace please ?

What other development cycle do you propose to prevent RESET LOOP and guarantee proper deterministic nRF91 initialization please ?

Please understand that we do require proper and convenient development cycle and we do not know how to that because nRF91 does not behave according description from developers and modem source code is closed, so do not have any other affordable way how to find way than asking for support.

Kind regards,
Michal

[Øyvind]

Thanks for providing this clarification. I've forwarded this to our modem team. 

Kind regards,
Øyvind

[Øyvind]

Hello again, 

I've got some feedback based on the last modem trace that you provided. From this our nRF91 team has the following feedback:

Based on the log, the device does not wait 60s+ after successful Attach before triggering reset.

00:00:17.284606  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:00:29.912078 L23_AT_STRING AT_STRING => +CFUN=1 
00:00:37.004303  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:00:47.108367 L23_AT_STRING AT_STRING => +CFUN=1 
00:00:54.326721  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:01:04.556671 L23_AT_STRING AT_STRING => +CFUN=1 
00:01:11.758941  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:01:22.482543 L23_AT_STRING AT_STRING => +CFUN=1 
00:01:29.760192  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:01:40.499420 L23_AT_STRING AT_STRING => +CFUN=1 
00:02:05.188568  NAS_PDU_ATTACH_COMPLETE_W_ACTIVATE_DEFAULT_EPS_BEARER_CONTEXT_ACCEPT [074300035200C2] 
00:02:17.234619 L23_AT_STRING AT_STRING => +CFUN=1 

This is the reason why the reset counter keeps increasing until there has been 7 resets. At that point the reset loop restriction is activated. You need to ensure that you wait at least 60 seconds after successful Attach before triggering the reset. This is to ensure that the reset counter does not increase. 

It is also possible to clear an active reset loop restriction by factory reset.

Based on this information, our nRF91 team informs me that you need

1. Wait at least 60 seconds before reset OR
2. Count each attaches and then wait 60 seconds after 4th successful attach. (+CGATT)
3. If above is not possible, do a factory reset (%XFACTORYRESET) after the RESET LOOP hits during 7th attach attempt

Kind regards,
Øyvind

[Michal Mühlpachr]

Hello again,

this trace is not from trace-2022-03-28T21-28-11.914Z.bin unfortunately who was collected to show that even 120+ seconds does not help.

Would you be so kind and check correct trace please ?

Regards,
Michal

[Michal Mühlpachr]

Hi,

I collected trace again together with AT dialogue log, both are below.

It is obvious, that even 120+ delay between attach and REST by pin does not prevent RESET LOOP.

Regads,
Michal

trace-2022-04-05T22-07-42.333Z.bin

First number on each line is time in seconds since test start, second number is relative time in seconds since cycle start.

<nRF9160DK power cycle>
========== CYCLE: 1 ========== Wed Apr 6 00:07:43 2022
0.31 0.00 <RESET by pin>
1.43 1.12 <WAKEUP by pin>
2.22 1.91 Ready
2.23 1.92 AT
2.26 1.96 OK
2.28 1.97 AT%XMODEMTRACE=1,2
2.31 2.00 OK
2.33 2.02 AT%MDMEV=1
2.36 2.05 OK
2.38 2.07 AT%HWVERSION
2.41 2.10 %HWVERSION: nRF9160 SICA BQA
2.42 2.11 OK
2.44 2.13 AT%SHORTSWVER
2.47 2.16 %SHORTSWVER: nrf9160_1.3.1
2.49 2.18 OK
2.50 2.19 AT%XPOFWARN=1,30
2.55 2.24 OK
2.56 2.25 AT%XSYSTEMMODE=0,1,0,0
2.61 2.30 OK
2.63 2.32 AT%REL14FEAT=1,1,1,1,0
2.66 2.35 OK
2.67 2.36 AT%RAI=1
2.71 2.40 OK
2.72 2.41 AT%XDATAPRFL=0
2.75 2.44 OK
2.77 2.46 AT%XSIM=1
2.80 2.49 OK
2.81 2.51 AT%XNETTIME=1
2.85 2.54 OK
2.86 2.55 AT+CEREG=5
2.89 2.58 OK
2.91 2.60 AT+CGEREP=1
2.94 2.63 OK
2.96 2.65 AT+CSCON=1
2.99 2.68 OK
3.00 2.69 AT+CPSMS=1,,,"00111000","00000000"
3.05 2.74 OK
3.07 2.76 AT+CNEC=24
3.10 2.79 OK
3.11 2.80 AT+CMEE=1
3.14 2.83 OK
3.16 2.85 AT+CEPPI=1
3.19 2.88 OK
3.21 2.90 AT#XSLEEP=2
3.24 2.93 OK
4.38 4.07 <WAKEUP by pin>
4.48 4.17 Ready
4.50 4.19 AT%XMODEMTRACE=1,2
4.53 4.22 OK
4.55 4.24 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
4.59 4.28 OK
4.61 4.30 AT+COPS=1,2,"23003"
4.66 4.35 OK
4.67 4.36 AT+CGDCONT=1,"IP","hardwario.com"
4.70 4.39 OK
4.72 4.41 AT+CFUN=1
4.83 4.52 OK
5.73 5.42 %XSIM: 1
5.75 5.44 AT+CGSN
5.78 5.47 352656106109476
5.80 5.49 OK
5.81 5.50 AT+CIMI
5.84 5.53 901288000012723
5.86 5.55 OK
10.91 10.60 +CEREG: 2,"AE38","000AC51F",9
11.59 11.28 +CSCON: 1
12.76 12.45 +CGEV: ME PDN ACT 0,0
12.79 12.48 +CNEC_ESM: 50,0
12.82 12.51 %MDMEV: SEARCH STATUS 2
12.85 12.54 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 2 ========== Wed Apr 6 00:09:56 2022
133.18 0.00 <RESET by pin>
134.29 1.12 <WAKEUP by pin>
135.08 1.90 Ready
135.10 1.92 AT
135.13 1.95 OK
135.14 1.97 AT%XMODEMTRACE=1,2
135.17 2.00 OK
135.19 2.01 AT%MDMEV=1
135.22 2.04 OK
135.24 2.06 AT%HWVERSION
135.27 2.09 %HWVERSION: nRF9160 SICA BQA
135.28 2.11 OK
135.30 2.12 AT%SHORTSWVER
135.33 2.15 %SHORTSWVER: nrf9160_1.3.1
135.35 2.17 OK
135.36 2.18 AT%XPOFWARN=1,30
135.41 2.23 OK
135.42 2.25 AT%XSYSTEMMODE=0,1,0,0
135.47 2.29 OK
135.49 2.31 AT%REL14FEAT=1,1,1,1,0
135.52 2.34 OK
135.53 2.36 AT%RAI=1
135.56 2.39 OK
135.58 2.40 AT%XDATAPRFL=0
135.61 2.43 OK
135.63 2.45 AT%XSIM=1
135.66 2.48 OK
135.67 2.50 AT%XNETTIME=1
135.70 2.53 OK
135.72 2.54 AT+CEREG=5
135.75 2.58 OK
135.77 2.59 AT+CGEREP=1
135.80 2.62 OK
135.81 2.64 AT+CSCON=1
135.84 2.67 OK
135.86 2.68 AT+CPSMS=1,,,"00111000","00000000"
135.89 2.71 OK
135.91 2.73 AT+CNEC=24
135.94 2.76 OK
135.95 2.78 AT+CMEE=1
135.98 2.81 OK
136.00 2.82 AT+CEPPI=1
136.03 2.85 OK
136.05 2.87 AT#XSLEEP=2
136.08 2.90 OK
137.20 4.03 <WAKEUP by pin>
137.31 4.14 Ready
137.33 4.15 AT%XMODEMTRACE=1,2
137.37 4.20 OK
137.39 4.21 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
137.43 4.26 OK
137.45 4.27 AT+COPS=1,2,"23003"
137.49 4.32 OK
137.51 4.33 AT+CGDCONT=1,"IP","hardwario.com"
137.54 4.36 OK
137.56 4.38 AT+CFUN=1
137.66 4.49 OK
138.57 5.39 %XSIM: 1
138.59 5.41 AT+CGSN
138.62 5.44 352656106109476
138.63 5.46 OK
138.65 5.47 AT+CIMI
138.68 5.50 901288000012723
138.70 5.52 OK
144.02 10.85 +CEREG: 2,"AE38","000AC51F",9
144.71 11.53 +CSCON: 1
145.92 12.74 +CGEV: ME PDN ACT 0,0
145.95 12.78 +CNEC_ESM: 50,0
145.98 12.81 %MDMEV: SEARCH STATUS 2
146.01 12.84 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 3 ========== Wed Apr 6 00:12:09 2022
266.35 0.00 <RESET by pin>
267.47 1.12 <WAKEUP by pin>
268.26 1.92 Ready
268.28 1.93 AT
268.31 1.96 OK
268.33 1.98 AT%XMODEMTRACE=1,2
268.36 2.01 OK
268.37 2.03 AT%MDMEV=1
268.40 2.06 OK
268.42 2.07 AT%HWVERSION
268.45 2.10 %HWVERSION: nRF9160 SICA BQA
268.47 2.12 OK
268.48 2.14 AT%SHORTSWVER
268.51 2.17 %SHORTSWVER: nrf9160_1.3.1
268.53 2.18 OK
268.55 2.20 AT%XPOFWARN=1,30
268.59 2.24 OK
268.61 2.26 AT%XSYSTEMMODE=0,1,0,0
268.65 2.31 OK
268.67 2.32 AT%REL14FEAT=1,1,1,1,0
268.70 2.35 OK
268.72 2.37 AT%RAI=1
268.75 2.40 OK
268.76 2.42 AT%XDATAPRFL=0
268.79 2.45 OK
268.81 2.46 AT%XSIM=1
268.84 2.49 OK
268.86 2.51 AT%XNETTIME=1
268.89 2.54 OK
268.90 2.56 AT+CEREG=5
268.93 2.59 OK
268.95 2.60 AT+CGEREP=1
268.98 2.64 OK
269.00 2.65 AT+CSCON=1
269.03 2.68 OK
269.04 2.70 AT+CPSMS=1,,,"00111000","00000000"
269.09 2.74 OK
269.11 2.76 AT+CNEC=24
269.14 2.79 OK
269.15 2.81 AT+CMEE=1
269.18 2.84 OK
269.20 2.85 AT+CEPPI=1
269.23 2.88 OK
269.25 2.90 AT#XSLEEP=2
269.28 2.93 OK
270.42 4.07 <WAKEUP by pin>
270.52 4.18 Ready
270.54 4.19 AT%XMODEMTRACE=1,2
270.57 4.22 OK
270.59 4.24 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
270.63 4.29 OK
270.65 4.30 AT+COPS=1,2,"23003"
270.70 4.35 OK
270.71 4.37 AT+CGDCONT=1,"IP","hardwario.com"
270.76 4.41 OK
270.77 4.43 AT+CFUN=1
270.88 4.54 OK
271.78 5.44 %XSIM: 1
271.80 5.45 AT+CGSN
271.83 5.48 352656106109476
271.85 5.50 OK
271.86 5.52 AT+CIMI
271.89 5.55 901288000012723
271.91 5.56 OK
277.14 10.79 +CEREG: 2,"AE38","000AC51F",9
277.83 11.48 +CSCON: 1
279.27 12.92 +CGEV: ME PDN ACT 0,0
279.30 12.95 +CNEC_ESM: 50,0
279.33 12.98 %MDMEV: SEARCH STATUS 2
279.36 13.01 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 4 ========== Wed Apr 6 00:14:22 2022
399.70 0.00 <RESET by pin>
400.81 1.11 <WAKEUP by pin>
401.60 1.91 Ready
401.62 1.92 AT
401.65 1.95 OK
401.66 1.97 AT%XMODEMTRACE=1,2
401.70 2.00 OK
401.71 2.01 AT%MDMEV=1
401.74 2.05 OK
401.76 2.06 AT%HWVERSION
401.79 2.09 %HWVERSION: nRF9160 SICA BQA
401.81 2.11 OK
401.82 2.12 AT%SHORTSWVER
401.85 2.16 %SHORTSWVER: nrf9160_1.3.1
401.87 2.17 OK
401.88 2.19 AT%XPOFWARN=1,30
401.93 2.23 OK
401.95 2.25 AT%XSYSTEMMODE=0,1,0,0
401.99 2.30 OK
402.01 2.31 AT%REL14FEAT=1,1,1,1,0
402.04 2.34 OK
402.05 2.36 AT%RAI=1
402.08 2.39 OK
402.10 2.40 AT%XDATAPRFL=0
402.13 2.43 OK
402.15 2.45 AT%XSIM=1
402.18 2.48 OK
402.19 2.50 AT%XNETTIME=1
402.23 2.53 OK
402.24 2.54 AT+CEREG=5
402.27 2.57 OK
402.29 2.59 AT+CGEREP=1
402.32 2.62 OK
402.34 2.64 AT+CSCON=1
402.37 2.67 OK
402.38 2.68 AT+CPSMS=1,,,"00111000","00000000"
402.43 2.73 OK
402.44 2.75 AT+CNEC=24
402.48 2.78 OK
402.49 2.79 AT+CMEE=1
402.52 2.83 OK
402.54 2.84 AT+CEPPI=1
402.57 2.87 OK
402.59 2.89 AT#XSLEEP=2
402.62 2.92 OK
403.74 4.05 <WAKEUP by pin>
403.85 4.15 Ready
403.87 4.17 AT%XMODEMTRACE=1,2
403.90 4.20 OK
403.91 4.22 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
403.96 4.26 OK
403.98 4.28 AT+COPS=1,2,"23003"
404.02 4.32 OK
404.04 4.34 AT+CGDCONT=1,"IP","hardwario.com"
404.08 4.39 OK
404.10 4.40 AT+CFUN=1
404.21 4.51 OK
405.12 5.42 %XSIM: 1
405.13 5.44 AT+CGSN
405.16 5.47 352656106109476
405.18 5.48 OK
405.20 5.50 AT+CIMI
405.23 5.53 901288000012723
405.24 5.54 OK
410.26 10.56 +CEREG: 2,"AE38","000AC51F",9
410.95 11.25 +CSCON: 1
412.19 12.49 +CGEV: ME PDN ACT 0,0
412.22 12.52 +CNEC_ESM: 50,0
412.25 12.55 %MDMEV: SEARCH STATUS 2
412.28 12.58 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 5 ========== Wed Apr 6 00:16:35 2022
532.62 0.00 <RESET by pin>
533.74 1.12 <WAKEUP by pin>
534.54 1.92 Ready
534.55 1.93 AT
534.58 1.97 OK
534.60 1.98 AT%XMODEMTRACE=1,2
534.63 2.01 OK
534.65 2.03 AT%MDMEV=1
534.68 2.06 OK
534.70 2.08 AT%HWVERSION
534.73 2.11 %HWVERSION: nRF9160 SICA BQA
534.74 2.12 OK
534.76 2.14 AT%SHORTSWVER
534.79 2.17 %SHORTSWVER: nrf9160_1.3.1
534.80 2.18 OK
534.82 2.20 AT%XPOFWARN=1,30
534.87 2.25 OK
534.88 2.26 AT%XSYSTEMMODE=0,1,0,0
534.93 2.31 OK
534.94 2.32 AT%REL14FEAT=1,1,1,1,0
534.97 2.35 OK
534.99 2.37 AT%RAI=1
535.02 2.40 OK
535.03 2.42 AT%XDATAPRFL=0
535.07 2.45 OK
535.08 2.46 AT%XSIM=1
535.11 2.49 OK
535.13 2.51 AT%XNETTIME=1
535.16 2.54 OK
535.18 2.56 AT+CEREG=5
535.21 2.59 OK
535.22 2.60 AT+CGEREP=1
535.25 2.64 OK
535.27 2.65 AT+CSCON=1
535.30 2.68 OK
535.32 2.70 AT+CPSMS=1,,,"00111000","00000000"
535.36 2.74 OK
535.38 2.76 AT+CNEC=24
535.41 2.79 OK
535.42 2.81 AT+CMEE=1
535.46 2.84 OK
535.47 2.85 AT+CEPPI=1
535.50 2.89 OK
535.52 2.90 AT#XSLEEP=2
535.55 2.93 OK
536.69 4.07 <WAKEUP by pin>
536.80 4.18 Ready
536.81 4.20 AT%XMODEMTRACE=1,2
536.85 4.23 OK
536.86 4.24 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
536.91 4.29 OK
536.92 4.30 AT+COPS=1,2,"23003"
536.97 4.35 OK
536.99 4.37 AT+CGDCONT=1,"IP","hardwario.com"
537.03 4.42 OK
537.05 4.43 AT+CFUN=1
537.16 4.54 OK
538.06 5.45 %XSIM: 1
538.08 5.46 AT+CGSN
538.11 5.49 352656106109476
538.13 5.51 OK
538.14 5.52 AT+CIMI
538.17 5.56 901288000012723
538.19 5.57 OK
543.38 10.76 +CEREG: 2,"AE38","000AC51F",9
544.07 11.45 +CSCON: 1
545.13 12.51 +CGEV: ME PDN ACT 0,0
545.16 12.54 +CNEC_ESM: 50,0
545.19 12.57 %MDMEV: SEARCH STATUS 2
545.23 12.61 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 6 ========== Wed Apr 6 00:18:48 2022
665.57 0.00 <RESET by pin>
666.68 1.11 <WAKEUP by pin>
667.46 1.89 Ready
667.48 1.91 AT
667.51 1.94 OK
667.52 1.95 AT%XMODEMTRACE=1,2
667.55 1.99 OK
667.57 2.00 AT%MDMEV=1
667.60 2.03 OK
667.62 2.05 AT%HWVERSION
667.65 2.08 %HWVERSION: nRF9160 SICA BQA
667.66 2.10 OK
667.68 2.11 AT%SHORTSWVER
667.71 2.14 %SHORTSWVER: nrf9160_1.3.1
667.73 2.16 OK
667.74 2.18 AT%XPOFWARN=1,30
667.79 2.22 OK
667.81 2.24 AT%XSYSTEMMODE=0,1,0,0
667.85 2.28 OK
667.87 2.30 AT%REL14FEAT=1,1,1,1,0
667.90 2.33 OK
667.91 2.34 AT%RAI=1
667.94 2.38 OK
667.96 2.39 AT%XDATAPRFL=0
667.99 2.42 OK
668.01 2.44 AT%XSIM=1
668.04 2.47 OK
668.05 2.49 AT%XNETTIME=1
668.09 2.52 OK
668.10 2.53 AT+CEREG=5
668.13 2.56 OK
668.15 2.58 AT+CGEREP=1
668.18 2.61 OK
668.19 2.62 AT+CSCON=1
668.22 2.65 OK
668.24 2.67 AT+CPSMS=1,,,"00111000","00000000"
668.29 2.72 OK
668.30 2.73 AT+CNEC=24
668.33 2.76 OK
668.35 2.78 AT+CMEE=1
668.38 2.81 OK
668.40 2.83 AT+CEPPI=1
668.43 2.86 OK
668.44 2.87 AT#XSLEEP=2
668.47 2.90 OK
669.60 4.03 <WAKEUP by pin>
669.71 4.14 Ready
669.72 4.15 AT%XMODEMTRACE=1,2
669.75 4.19 OK
669.77 4.20 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
669.82 4.25 OK
669.83 4.26 AT+COPS=1,2,"23003"
669.88 4.31 OK
669.89 4.32 AT+CGDCONT=1,"IP","hardwario.com"
669.94 4.37 OK
669.96 4.39 AT+CFUN=1
670.06 4.50 OK
670.97 5.40 %XSIM: 1
670.99 5.42 AT+CGSN
671.02 5.45 352656106109476
671.03 5.47 OK
671.05 5.48 AT+CIMI
671.08 5.51 901288000012723
671.10 5.53 OK
676.50 10.93 +CEREG: 2,"AE38","000AC51F",9
677.19 11.62 +CSCON: 1
678.72 13.15 +CGEV: ME PDN ACT 0,0
678.75 13.18 +CNEC_ESM: 50,0
678.78 13.21 %MDMEV: SEARCH STATUS 2
678.81 13.24 +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"
Wait 2m
========== CYCLE: 7 ========== Wed Apr 6 00:21:02 2022
799.14 0.00 <RESET by pin>
800.27 1.12 <WAKEUP by pin>
801.06 1.92 Ready
801.08 1.93 AT
801.11 1.96 OK
801.12 1.98 AT%XMODEMTRACE=1,2
801.16 2.01 OK
801.17 2.03 AT%MDMEV=1
801.20 2.06 OK
801.22 2.07 AT%HWVERSION
801.26 2.12 %HWVERSION: nRF9160 SICA BQA
801.28 2.14 OK
801.30 2.15 AT%SHORTSWVER
801.33 2.18 %SHORTSWVER: nrf9160_1.3.1
801.34 2.20 OK
801.36 2.21 AT%XPOFWARN=1,30
801.40 2.26 OK
801.42 2.27 AT%XSYSTEMMODE=0,1,0,0
801.47 2.32 OK
801.48 2.34 AT%REL14FEAT=1,1,1,1,0
801.51 2.37 OK
801.53 2.38 AT%RAI=1
801.56 2.42 OK
801.58 2.43 AT%XDATAPRFL=0
801.61 2.46 OK
801.62 2.48 AT%XSIM=1
801.66 2.51 OK
801.67 2.53 AT%XNETTIME=1
801.70 2.56 OK
801.72 2.57 AT+CEREG=5
801.75 2.60 OK
801.76 2.62 AT+CGEREP=1
801.80 2.65 OK
801.81 2.67 AT+CSCON=1
801.84 2.70 OK
801.86 2.71 AT+CPSMS=1,,,"00111000","00000000"
801.91 2.76 OK
801.92 2.78 AT+CNEC=24
801.95 2.81 OK
801.97 2.82 AT+CMEE=1
802.00 2.85 OK
802.01 2.87 AT+CEPPI=1
802.04 2.90 OK
802.06 2.92 AT#XSLEEP=2
802.09 2.95 OK
803.23 4.09 <WAKEUP by pin>
803.34 4.20 Ready
803.36 4.21 AT%XMODEMTRACE=1,2
803.40 4.26 OK
803.42 4.27 AT%XBANDLOCK=1,"0000000000000000000000000000000000000000000000000000000000001000000010000000100010011010"
803.47 4.32 OK
803.48 4.34 AT+COPS=1,2,"23003"
803.53 4.38 OK
803.55 4.40 AT+CGDCONT=1,"IP","hardwario.com"
803.59 4.45 OK
803.61 4.46 AT+CFUN=1
803.72 4.57 OK
803.75 4.60 %MDMEV: RESET LOOP
804.62 5.48 %XSIM: 1
804.64 5.50 AT+CGSN
804.67 5.53 352656106109476
804.69 5.54 OK
804.70 5.56 AT+CIMI
804.73 5.59 901288000012723
804.75 5.60 OK
809.60 10.46 +CEREG: 2,"AE38","000AC51F",9

[Øyvind]

Hello Michal, 

Our expert has looked at the correct trace that shows the same behavior

00:00:00.104095 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset
00:00:07.599090 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:00:29.531158 STARTUP_FUNCTION_RUN L23 Protocol init  // <- reset after 22s
00:00:41.269745 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:01:02.012634 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset after 21s
00:01:10.174042 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:01:31.039642 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset after 21s
00:01:43.950745 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:02:04.542755 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset after 21s
00:02:13.114563 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:02:42.965027 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset after 20s
00:02:53.406464 L23_AT_STRING AT_STRING <= +CEREG: 5,"AE38","000AC51F",9,,,"00000000","00111000"\r\n  // Attach completed
00:03:14.374512 STARTUP_FUNCTION_RUN L23 Protocol init // <- reset after 21s
00:03:17.692444 L23_AT_STRING AT_STRING <= %MDMEV: RESET LOOP\r\n // <- Reset loop restriction activated

1. Must wait over 60s after Attach before triggering reset. Attach completion can be noticed by subscribing and following +CEREG notification.

2. If the Reset loop restriction was activated by mistake in step 1, then use AT%XFACTORYRESET=0 to remove the restriction. Reset loop restriction activation can be noticed by subscribing and following %MDMEV notification.

Kind regards,
Øyvind