Recommended modem firmware upgrade path

[dubois]

I'm in the process of upgrading one of our applications from NCS 2.6.1 to 3.0.1. According to this document, the only versions of NCS that support modem firmware 2.0.1 and 2.0.2 are NCS 2.7.0 and NCS 2.8.0. The application currently uses modem firmware 2.0.1.

My plan is to perform two updates:

1. First update:
   
   1. Upgrade the application to a version built against NCS 2.8.0. The existing modem firmware should still be compatible after this update.
   2. Boot the upgraded app
2. Second update:
   1. Upgrade the modem to version 2.0.2. The now-running application from the first update should be compatible after this step
   2. Upgrade the application to a version built against NCS 3.0.1
   3. Boot the upgraded app

If either the first update or step 2.b fails, the running application should still be able to use the modem to attempt the update again.

Is this procedure necessary, or is it safe to go directly to an application built against NCS 3.0.1, i.e., potentially leaving the device in a state where the modem firmware is 2.0.2 and the application uses NCS 2.6.1?

[Hakon]

Hello,

Is this procedure necessary, or is it safe to go directly to an application built against NCS 3.0.1, i.e., potentially leaving the device in a state where the modem firmware is 2.0.2 and the application uses NCS 2.6.1?

If you run the quick start app it will flash mfw 2.0.2 and NCS v3.0.0 together.

So I doubt that using NCS v3.0.1 with mfw 2.0.2 will be problematic at all. Do you have access to any debug interface so you can erase and flash your board?

[dubois]

Hi Hakon,

I understand that NCS 3.0.1 is compatible with MFW 2.0.2 (I saw this on the chart that's linked in the question).

My question boils down to: if I do not use a two-stage update, and instead use a single update to attempt upgrading from NCS2.6.1+MFW2.0.1 to NCS3.0.1+MFW2.0.2, and the modem upgrade to 2.0.2 succeeds but the application upgrade to 3.0.1 fails, will the existing NCS 2.6.1 application be able to use the new modem firmware reliably enough to attempt downloading and retrying the update again? I.e., the chart says that NCS 2.6.0 is incompatible with MFW 2.0.2.