Device Tree replacement for deprecated Partition Manager is ridiculously poorly documented at this NCS v3.4.1 stage

[Burt]

Hi,

I am going nuts with the device tree replacement for PM that seems to cover about 1 case out of a larger number of possibilities. Please give me the overlay files and related information to set up NSIB bootloader, NO MCUBOOT, TF-M, and External Flash for nRF9160DK. You quite clearly state that this is a valid configuration on your README.html#bootloader-flash-layout. But it looks like you have thrown up all sorts of road blocks to most configurations when you tried to replace Partition Manager with DTS. We know from the documentation that Partition Manager was deprecated last quarter, June-August, the third quarter of 2026.

I also would like the overlay file that works with NO NSIB, MCUBOOT, TF-M, and External Flash.

I also would like the overlay file that works with NO NSIB, NO MCUBOOT, TF-M, and External Flash.

The proof that your documentation needs lots of help is that when I try to use AI to solve these problems, it ends up in a divergence rather than convergence.

Thank you very much for help.

Regards,

Burt Silverman

[Simonr]

Hi Burt

I assume you refer to the migration documentation for migrating partition configuration from Partition manager to DTS as lackluster? If not, I recommend going through the migration steps there for your project. We do work on improving our documentation where we can, and appreciate constructive feedback to improve the experience.

I have generated some overlay files for the nRF9160 DK with the requested settings. Please note that these were generated with the help from Claude, and have not been tested extensively, so they should be tested/reviewed thoroughly on your side as well before implementing them in a custom application. Tested with the tfm_hello_world sample project in NCS 3.4.0 on my end.

I ran into some issues that I'll need to look further into next week regarding the "NSIB bootloader, NO MCUBOOT, TF-M, and External Flash" file, but the other two without NSIB seem to work correct.

overlays.zip

Also, please share some details on what you're struggling with if you'd like to get to the bottom of the issues you're having on your end.

Best regards,

Simon

[Burt]

Hi Simon,

Thank you very much for a quick response.

I had in fact missed seeing the Migrating document section of the NCS documentation -- I was looking at sections dealing with NSIB and mcuboot, then trying to use Google AI and match things up to those. Also, while looking at NSIB documentation I also looked at nrf/dts/samples/cellular/* and noticed that there was not for the NSIB but no mcuboot case, and I thought maybe someone found it less interesting than the others. So I ended up trying to solve the case you are telling me is not simple, and, using Google AI, I ended up very frustrated! I am so glad to learn that it is not a simple case, and I look forward to your findings next week.

One other thing about the Migrating document -- it says "Use the following migration procedure for existing projects that still rely on Partition Manager except for the nrf91 Series devices." So it sounds like either that sentence can be removed, or else more updates to the procedure are needed.

I will test out what you gave me in overlays.zip. Thanks again.

Burt