MCUBOOT with nrf9161-sica

Question

I’m working on a custom board based on the nRF9160 (SICA variant) and trying to enable MCUboot + TF-M with sysbuild. I’m running into an issue where the system never reaches the application after MCUboot hands over control.

Environment

NCS version: 3.2.2
Zephyr: 4.2.99
Toolchain: NCS toolchain (default)
Board: custom (rit_nordic3_nrf9160/ns)
Using sysbuild with MCUboot and TF-M

Problem description

The device boots into MCUboot correctly, validates the image, and attempts to jump to slot0. However, nothing executes afterward:

No Zephyr banner
No TF-M logs (e.g. [Sec Thread] Secure image initializing!)
No RTT output
No UART output from the application

MCUboot log

*** Booting MCUboot v2.3.0-dev ***
I: Starting bootloader
...
I: Image version: v1.1.0
?: Jumping to the first image slot

After this line → system is silent

What we verified

MCUboot builds and runs correctly
Image is properly signed and validated (ECDSA OK)
Partition layout looks correct (slot0 @ 0x10000, slot1 @ 0x80000)
TF-M is being built (build/.../tfm exists)
Using sysbuild (--sysbuild)

What we tried

1. Logging / console debugging

Switched to RTT:

CONFIG_USE_SEGGER_RTT=y
CONFIG_LOG_BACKEND_RTT=y
CONFIG_RTT_CONSOLE=y
CONFIG_UART_CONSOLE=n

Result: still no output after MCUboot jump

2. UART console

Initially UART console worked for MCUboot logs
Disabled UART console → still no application output

3. Partition Manager

Verified layout using partition_manager_report
Matches expected MCUboot + TF-M layout

4. TF-M dependency check

Tried disabling TF-M → build fails due to missing psa/crypto.h
So TF-M is required in our application

5. DTS cleanup

We started with a minimal SICA DTS:

#include <nordic/nrf9160ns_sica.dtsi>

Then adjusted our board DTS to:

/dts-v1/;

#include <nordic/nrf9160ns_sica.dtsi>
#include "rit_nordic3_nrf9160-pinctrl.dtsi"
#include "rit_nordic3_nrf9160-partitioning.dtsi"
#include "rit_nordic3_nrf9160.dtsi"

/ {
    chosen {
        zephyr,flash = &flash0;
        zephyr,sram = &sram0_ns;
        zephyr,code-partition = &slot0_partition;
    };
};

Also removed:

duplicate includes
flash/sram overrides
extra soc {} node

Current understanding

It looks like:

MCUboot works and jumps correctly
Failure happens immediately after jump
TF-M does not seem to start at all
Likely a secure memory / SPU / TF-M platform integration issue

Given we are using the SICA variant, we suspect:

missing or incorrect secure attribution configuration
board DTS / platform not fully aligned with TF-M expectations

Questions

Is nrf9160ns_sica.dtsi alone sufficient for TF-M + MCUboot setups?
Are there additional required configurations for SPU / secure memory when using SICA?
Is there a reference board or example using SICA + TF-M + MCUboot?
What is the minimal set of requirements for a custom board DTS to work with TF-M?

Goal

We want:

MCUboot + TF-M working on a custom SICA-based board
Ability to run application (with console/menu) after boot

Any guidance or reference configuration would be greatly appreciated.

Thanks!