How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

RE: How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

Lukáš — Fri, 21 May 2021 10:05:29 GMT

Hello Heidi, we bricked our two DKs that were bought at the same time (approx. 1,5 years ago?). When it failed for the first time, we thought it is some kind of error, but then we tried to update the MFW on the second DK and it behaved exactly the same.

I sent you our details in a private message. Thanks a lot for your kindness and help!

RE: How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

Heidi — Fri, 21 May 2021 09:56:43 GMT

Hi,

So there have been some cases of the MFW update bricking very early versions of the nRF9160. But in that case, you should be been able to downgrade. to an earlier MFW version.

They still suspect that it's because of downgrade prevention. There are some early versions of nRF Programmer that enabled downgrade prevention by default.

Nevertheless, we will ship you new DKs. Please provide your address, full name, and phone number. How many of the kits are bricked?

Best regards,

Heidi

RE: How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

Lukáš — Thu, 20 May 2021 23:18:16 GMT

But I am talking about engineering revision DKs. Not B1 or B0 which are working fine. We tried to upload the MFW 1.3.0 via the Nordic Programmer app, but it failed after uploading the first file. Now it is not possible to upload any modem firmware and for each upload request it returns "Lowlevel error: Unknown value (ffffff23)". We didn't enable the %XPRODDONE of course. Only the firmware update to MFW 1.3.0 was performed. Now we have two DKs with nRF91 engineering revisions bricked.

Could you try it on your own? Grab nRF9160 DK with engineering revision of nRF91 and you should end up with the same result.

RE: How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

Heidi — Thu, 20 May 2021 12:10:22 GMT

Hi!!

"By default", It should be possible to downgrade to MFW 1.1.x and 1.2.x from MFW 1.3.0.

However, once you've enabled %XPRODDONE in the device(s), which enables downgrade prevention (security feature), it is not possible to downgrade anymore. This security feature prevents going back to previous MFW versions.

Could that be what happened here? In that case, new devices are needed.

RE: How to downgrade from MFW 1.3.0 and unbrick nRF9160 DK

Heidi — Tue, 18 May 2021 11:48:15 GMT

Hi!

Sorry about the late reply.

I don't know how to do this but I have asked the modem team and I will let you know as soon as I hear back.

Best regards,

Heidi