# Zena_CSS_Cfg2 11.31 build 25 Release Notes

## Zena_CSS_Cfg2 Release Notes

This document is Non-Confidential. Copyright © 2026 Arm Limited or its affiliates. All rights reserved. This document is protected by copyright and other intellectual property rights. Arm only permits use of this document if you have reviewed and accepted Arm's Proprietary notice found at the end of this document. This document was issued on 25 February 2026. The product version is 11.31. See also: Product and document information

## Intended audience

This document is for users of the Zena_CSS_Cfg2 FVP, who want to see details of how to get started with the FVP, and details of the latest changes.

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## Release overview

### Package description

This is a package containing the Zena_CSS_Cfg2 reference design FVP. These release notes describe the specific aspects and limitations of this release.

### Model version numbers

Run the model with the `--version` parameter to obtain the build version of the model.

## Introduction

These release notes relate to the Automotive Zena_CSS_Cfg2 FVP. This model implements the Automotive Zena_CSS_Cfg2 subsystem as specified by the hardware technical overview specifications, with additional system peripherals to create a system model capable of booting Linux.

## Architecture introduction

The Automotive ASD system architecture incorporates the latest generation of cores, interconnects, and other System IPs, into a design that addresses the expected requirements of the automotive markets.

These are the key components:

- Cortex-A720AE CPU.
- CMN-S3 interconnect.
- NI-710AE interconnect.
- Runtime Security Engine (RSE)
  - Root of trust of the system based on a single-core Cortex-M55.
- System Management Domain (SMD) peripherals
  - These implement power, reset and interrupt control for the system.
- Safety Island (SI).
  - Cluster 0 - Arm Cortex-R82AE with 2 cores in lock-step
  - Cluster 1 - Arm Cortex-R82AE with 4 cores
  - GIC-720AE Generic Interrupt Controller.
  - NI-710AE primary, secondary and MHU interconnects.
- System peripherals, including generic timers, watchdog timers, static RAMs and ROMs.
- GIC-720AE Generic Interrupt Controller.

## Limitations and known issues

The following Automotive Zena_CSS_Cfg2 subsystem components are not implemented:

- CoreSight
- Dynamic Memory Controller
- Safety Island cores have no low-latency peripheral port
- Safety Island PIK & Built-In Self-Test (BIST) are not modelled
- System Monitoring and Control Framework (SMCF)

## Changes in this release

- None. This is the first public release

## Installation instructions

FVPs are provided as simple packages to extract into a directory of your choice.

### Installing on Linux

1. Use a terminal to extract the `.tar.gz` archive:

       tar -xzf FVP_<package>_<version>_<build>_<arch>.tar.gz -C <install_path>

2. Confirm the FVP binary is working:

       <install_path>/bin/<FVP_Binary> --version

   You should see output displaying the FastModels FVP version.

### Installing on Windows

1. You can extract the '.zip' archive using File Explorer or an archive utility of your choice.

   To use File Explorer:

   1. Right-click on the '.zip' file
   2. Choose 'Extract All...'
   3. Select your destination folder, for example `C:\Program Files\Arm`, and extract.

2. Confirm the FVP binary is working:

       <install_path>\bin\<FVP_Binary>.exe --version

   You should see output displaying the FastModels FVP version.

## Running the model

Refer to the Fast Models User Guide for general instructions on running FVPs.

Refer to the Arm Automotive ASD technical overview for information on the compute subsystem and how to work with it.

This model is intended to be used with the Arm reference design software package

### Model parameters

Run the model with `--list-params` to get a list of available configuration parameters for the model. There might be new parameters in the FVP and which are not yet documented in the Fast Models documentation. Many of these provide assistance in bringing up bare-metal software on the FVP and will not be required if the model is run with the Arm firmware supplied.

## Proprietary Notice

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Your access to the information in this document is conditional upon your acceptance that you will not use or permit others to use the information for the purposes of determining whether implementations infringe any third party patents.

The content of this document is informational only. Any solutions presented herein are subject to changing conditions, information, scope, and data. This document was produced using reasonable efforts based on information available as of the date of issue of this document. The scope of information in this document may exceed that which Arm is required to provide, and such additional information is merely intended to further assist the recipient and does not represent Arm's view of the scope of its obligations. You acknowledge and agree that you possess the necessary expertise in system security and functional safety and that you shall be solely responsible for compliance with all legal, regulatory, safety and security related requirements concerning your products, notwithstanding any information or support that may be provided by Arm herein. In addition, you are responsible for any applications which are used in conjunction with any Arm technology described in this document, and to minimize risks, adequate design and operating safeguards should be provided for by you.

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## Product and document information

Read the information in these sections to understand the release status of the product and documentation, and the conventions used in the Arm documents.

### Product status

All products and Services provided by Arm require deliverables to be prepared and made available at different levels of completeness. The information in this document indicates the appropriate level of completeness for the associated deliverables.

#### Product completeness status

The information in this document is Final, that is for a developed product.

#### Product revision status

The 11.31 identifier indicates the revision status of the product described in this manual.

### Conventions

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