# SARA R4 Unresponsive after initially OK

**URL:** <https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659>\
**Category:** MKR NB 1500\
**Created:** [April 22, 2024, 8:11am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659 "2024-04-22T08:11:52Z")\
**Posts on this page:** 7\
**Page:** 1

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**Author:** ![dansiviter](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/dansiviter/32/1061888_2.png) [@dansiviter](https://forum.arduino.cc/u/dansiviter)\
**Post date:** [April 22, 2024, 8:11am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/1 "2024-04-22T08:11:53Z")

</div>

I'm getting a strange issue after upgrading to the Arduino Support recommended version of A.02.16. The Modem initially starts fine and responds normally, however after approx. 30 seconds it simply stops responding to commands. The only thing I've found to get it to start again is cycling the power. Here's a little snipped from the M-Center logs:

```arduino
[08:45:52.925] AT+CREG?
[08:45:52.957] 
[08:45:52.957] 
[08:45:52.957] +CREG: 0,2
[08:45:52.957] 
[08:45:52.957] OK
[08:46:27.866] 
[08:46:27.866] AT // <-- no longer responds
[08:46:28.908] ATE0
[08:46:29.949] AT+CMEE=2
[08:46:30.982] AT+CGMI
[08:46:33.063] AT+CGMM

```

This is happening on two separate boards. Arduino support have said they only recommend A.02.16 firmware as they believe A.02.21 it has more bugs. Is this a common issue and is there any merit in trying A.02.19 or A.02.21 to address this?

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**Author:** ![Dozie](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/dozie/32/239024_2.png) [@Dozie](https://forum.arduino.cc/u/Dozie)\
**Post date:** [April 22, 2024, 10:05am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/2 "2024-04-22T10:05:26Z")

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Reset the board by double tapping the reset button and uploading a blink sketch. Afterwards, upload "SerialSARAPassthrough sketch" and set the serial monitor to baud = 115200. Then try again to use AT commmands.

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<div class="post-metadata">

**Author:** ![dansiviter](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/dansiviter/32/1061888_2.png) [@dansiviter](https://forum.arduino.cc/u/dansiviter)\
**Post date:** [April 22, 2024, 10:54am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/3 "2024-04-22T10:54:11Z")

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Hi @Dozie, that looks to have helped one of the boards but the other one is still having issues:

```arduino
[11:51:11.476] +CGREG: 0,4
[11:51:11.476] 
[11:51:11.476] OK
[11:51:11.539] 
[11:51:11.539] AT+CREG?
[11:51:11.555] 
[11:51:11.555] 
[11:51:11.555] +CREG: 0,2
[11:51:11.555] 
[11:51:11.555] OK
[11:51:31.195] 
[11:51:31.195] AT+CCLK? // <-- Only 20 seconds this time before unresponsive
[11:52:22.234] AT
[11:52:23.272] ATE0
[11:52:24.310] AT+CMEE=2
[11:52:25.339] AT+CGMI
[11:52:27.411] AT+CGMM
[11:52:29.460] ATI0
[11:52:31.520] AT+CGMR

```

Any other suggestions?

I probably should also mention that this one also refuses to find a MNO profile too:

```arduino
[11:56:26.667] AT+URAT=8
[11:56:26.682] 
[11:56:26.682] AT+URAT=8
[11:56:26.682] 
[11:56:26.682] OK
[11:56:29.993] 
[11:56:29.993] AT+UMNOPROF=1
[11:56:30.008] 
[11:56:30.008] AT+UMNOPROF=1
[11:56:30.008] 
[11:56:30.008] OK
[11:56:33.221] 
[11:56:33.221] AT+CFUN=15
[11:56:33.253] 
[11:56:33.253] AT+CFUN=15
[11:56:33.253] 
[11:56:33.253] OK
[11:56:37.172] 
[11:56:37.172] AT+UMNOPROF?
[11:56:37.534] 
[11:56:37.534] AT+UMNOPROF?
[11:56:37.534] 
[11:56:37.534] +UMNOPROF: 0

```

The other board finds `19 Vodafone` but this one doesn't with same antenna and SIM.

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<div class="post-metadata">

**Author:** ![Dozie](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/dozie/32/239024_2.png) [@Dozie](https://forum.arduino.cc/u/Dozie)\
**Post date:** [April 22, 2024, 10:58am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/4 "2024-04-22T10:58:39Z")

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The trick should work for both. Try repeating it.

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<div class="post-metadata">

**Author:** ![dansiviter](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/dansiviter/32/1061888_2.png) [@dansiviter](https://forum.arduino.cc/u/dansiviter)\
**Post date:** [April 22, 2024, 11:17am UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/5 "2024-04-22T11:17:27Z")

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Unfortunately, contrary to my earlier reports it's still happening on both, regardless of how many times I install blinky then `SerialSARAPassthrough`. They both become unresponsive after a short, albeit random, amount of time. I'm inclined to try a newer firmware to see if that fixes the issue.

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<div class="post-metadata">

**Author:** ![n9p7v](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/n9p7v/32/1106390_2.png) [@n9p7v](https://forum.arduino.cc/u/n9p7v)\
**Post date:** [June 12, 2024, 2:18pm UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/6 "2024-06-12T14:18:21Z")

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Hello, did you find the reason of unresponsiveness? I face the same issue after upgrade to the latest firmware (05.12,A.02.21) obtained from ublox.

EDIT: I found that somehow the power saving had been enabled after the firmware update, and that was causing the unresponsiveness modem. I disabled it with m-center and now, albeit I'm facing other issues, is working excellent.

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<div class="post-metadata">

**Author:** ![system](https://dub1.discourse-cdn.com/arduino/user_avatar/forum.arduino.cc/system/32/1140315_2.png) [@system](https://forum.arduino.cc/u/system)\
**Post date:** [December 9, 2024, 2:18pm UTC](https://forum.arduino.cc/t/sara-r4-unresponsive-after-initially-ok/1250659/7 "2024-12-09T14:18:41Z")

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