Device not going to DFU mode on some devices

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 08 Apr 2024 05:58:30 GMT

We are getting another device. I will update. But with read back protection we would need to erase and the chip to read the CPU register, right? That is fine?

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 08 Apr 2024 05:41:36 GMT

I wanted you to read out the CPU registers without power-cycling the device. Please see if you can reproduce the problem again on this device, or try on another device with this problem.

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Sun, 07 Apr 2024 10:26:11 GMT

The device recovered after we tried to solder the SWD pins and device powered on.

What could be the reason. There are many devices showing this issue on field.

RE: Device not going to DFU mode on some devices

Vidar Berg — Tue, 19 Mar 2024 10:35:01 GMT

Hi Vishnu,

Perhaps you can probe the XTAL pins to see if there is any clock signal (this must be done when the chip is supposed to be in bootloader dfu mode). With readback protection enabled, there isn’t much debugging you can do. The only option is to try reprogramming the same firmware and hope that it does not recover the chip.

Best regards,

Vidar

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Tue, 19 Mar 2024 09:30:49 GMT

Hi Vidar,

We have managed to expose the SWD pins. Anything we can check?

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 15:07:12 GMT

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474234"]You can make a distribution packet that contains the SD+BL and application.[/quote]

Vidar Berg Regarding this. In both application and bootloader we were using s140 7.2. Now updating to 7.3.
Should we need to build bootloader with updated softdevice and then create the package with new bootloader+ 7.3 SD + new application with 7.3 support. Will the existing bootloader with 7.2 SD accepts new package? Anything needs to change?.

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 15:00:34 GMT

Yes, Readback protection is enabled. :(

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 14:58:37 GMT

Is readback protection enabled? If not, you can start by running 'nrfjprog --readregs' to read out the CPU registers. This may help reveal what state the device is in.

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 14:43:06 GMT

That is possible. What should we check?

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 13:52:08 GMT

Hi Vishnu,

I would have expected the WDT to trigger a reset and caused the bootloader to exit DFU mode and revert to the old application. Is it impossible to open the enclosure and access the SWD lines?

Best regards,

Vidar

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 13:47:37 GMT

Hi Vidar,

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474344"]Maybe the BLE transport is waiting for the crystal to start up, or do you have a WD enabled on DFU entry? [/quote]

WDT is enabled in the application and and WD settings is same as default settings in bootloader. Unchanged.

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474344"]I tried to replicate this scenario on my desk by using the buttonless application with the RC oscillator, and the bootloader with the default configuration, but did not experience any problems with DFU[/quote]

Even we are not able to replicating the issue on PCB here. But atleast 200-500 users faced this issue on field and we had to pull back the release.

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 13:27:15 GMT

Hi Vishnu,

This is interesting, the bootloader should time out and reset after 2 minutes of inactivity and fall back to the old application with the default configuration. The fact that it takes more than 15 minutes to recover suggests that there may be an issue with the clock source. Maybe the BLE transport is waiting for the crystal to start up, or do you have a WD enabled on DFU entry?

I tried to replicate this scenario on my desk by using the buttonless application with the RC oscillator, and the bootloader with the default configuration, but did not experience any problems with DFU.

Best regards,

Vidar

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 12:59:51 GMT

Hi Vidar,

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474319"]Is this behavior consistent on the failing devices? That is, do they always go "offline" for 15-20 minutes after a failed DFU attempt?[/quote]

We got only device back here and it was going offline for 15-20 minutes always on DFU attempt. Most devices would be facing the same.

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 12:36:57 GMT

Hi Vishnu,

[quote userid="130867" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474304"]Yes. The application is with internal RC and bootloader uses default external crystal settings. The device is fully enclosed and no debug pins available to debug. Anyway to recover this? [/quote]

Thanks for confirming.

[quote userid="130867" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474304"]It is trying to connect for few times and then disconnecting. After that it take 15-20 minutes to start advertising again with old application[/quote]

Is this behavior consistent on the failing devices? That is, do they always go "offline" for 15-20 minutes after a failed DFU attempt?

Best regards,

Vidar

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 12:08:41 GMT

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474298"]So, is the firmware application in the field running off the internal RC oscillator, while the bootloader uses the LF crystal? Have you tried to debug the bootloader when it's failing to enter DFU mode[/quote]

Yes. The application is with internal RC and bootloader uses default external crystal settings. The device is fully enclosed and no debug pins available to debug. Anyway to recover this?

It is trying to connect for few times and then disconnecting. After that it take 15-20 minutes to start advertising again with old application

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 12:01:03 GMT

[quote user="vishnu3391_uh"]No no. The current version on the field is have application with internal clock and bootloader with default settings. [/quote]

So, is the firmware application in the field running off the internal RC oscillator, while the bootloader uses the LF crystal? Have you tried to debug the bootloader when it's failing to enter DFU mode.

[quote user="vishnu3391_uh"]Is this because of the clock settings mismatch between app and bootloader on the existing version? [/quote]

It is possible, but it is not clear why only some devices are affected.

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 10:39:01 GMT

Hi Vidar,

Is this because of the clock settings mismatch between app and bootloader on the existing version? What are the possible reasons for this behavior? This is very critical blocker for us now. Without this we cannot release new build.

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 10:08:15 GMT

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474249"]What is failing? Is the DFU enter command returning with an error?[/quote]

It is not able to discover the device after sending DFU mode command? Attached the nRF connect logs.

devzone.nordicsemi.com/.../dfu-fail.txt

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 09:57:23 GMT

Hi Vishnu,

[quote userid="130867" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474246"] Yes we got one device back for troubleshooting and it is failing when attempting to enter DFU mode.[/quote]

What is failing? Is the DFU enter command returning with an error?

[quote userid="130867" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474246"]For this do we need to update the bootloader first to take new SD? If yes what is the change?[/quote]

Bootloader and Softdevice should updated in one-go as illustrated here: SoftDevice and bootloader

RE: Device not going to DFU mode on some devices

vishnu3391_uh — Mon, 18 Mar 2024 09:53:49 GMT

Hi Vidar,

No no. The current version on the field is have application with internal clock and bootloader with default settings. Now on top of this build some users are not able to update. Yes we got one device back for troubleshooting and it is failing when attempting to enter DFU mode. It is coming on many phone models.

[quote userid="4240" url="~/f/nordic-q-a/109378/device-not-going-to-dfu-mode-on-some-devices/474234"]You can make a distribution packet that contains the SD+BL and application.[/quote]

For this do we need to update the bootloader first to take new SD? If yes what is the change?

Thanks,

Vishnu

RE: Device not going to DFU mode on some devices

Vidar Berg — Mon, 18 Mar 2024 09:25:30 GMT

Hi Vishnu,

I don't think the different clock source configuration explains the DFU failure.The new clock configuration will not take effect until after the update is complete. Are you able to provide more information about when and where the DFU process is failing? Is the failure happening when attempting to enter DFU mode, or does it happen at some point during the firmware transfer? Also, do you have any data to check if the failure might be specific to certain phone models?

[quote user=""]What is the proper and best way to update SD and bootloader update in this scenarios.[/quote]

You can make a distribution packet that contains the SD+BL and application.

Best regards,

Vidar