Zephyr Kernel Simulation Deadlocks on Renode/nRF52840: NVIC Warnings, Hangs, and Compatibility Issues

[Mrham89]

Problem Summary

I am experiencing persistent kernel deadlocks and simulation incompatibility issues when attempting to run Zephyr RTOS applications on Renode with the nRF52840 target (specifically Arduino Nano 33 BLE Sense). The kernel fails to properly initialize or hangs during early boot stages, with NVIC-related warnings and thread/interrupt handling problems.

Hardware/Simulation Setup

• Target Board: nRF52840 (Arduino Nano 33 BLE Sense)
• Simulator: Renode (latest version)
• Zephyr Version: Latest (main branch)
• Host OS: [Specify your OS if relevant]

Symptoms

1. NVIC Warnings: Frequent warnings about NVIC (Nested Vectored Interrupt Controller) configuration issues
2. Boot Hangs: System hangs during kernel initialization, often in thread setup or interrupt configuration
3. Simulation Deadlocks: Complete simulation freeze with no forward progress
4. Peripheral Issues: Problems with UART and other peripheral initialization in simulation

Troubleshooting Attempts

I have conducted extensive troubleshooting to isolate the issue:

1. Bare-Metal UART Test

• Created a minimal bare-metal UART test bypassing the Zephyr kernel entirely
• Result: Still experienced issues, suggesting simulation-level problems

2. Kernel Bypass Tests

• Attempted to bypass various kernel subsystems to identify the failure point
• Result: Problems persist even with minimal kernel configuration

3. C# Peripheral Stubs (Renode)

• Investigated and attempted to create custom C# peripheral models in Renode
• Result: Some peripherals appear incomplete or not fully implemented for nRF52840

4. Configuration Variations

• Tested multiple Kconfig configurations
• Tried different optimization levels and debug settings
• Disabled various kernel features systematically
• Result: No configuration successfully resolves the deadlock

Community Findings

Based on research and community discussions, this appears to be a simulation completeness issue rather than a project misconfiguration:

• The nRF52840 peripheral models in Renode may not be fully complete
• Some critical interrupt handling paths may not be properly simulated
• NVIC timing and behavior may not fully match hardware
• This is not an isolated case - others have reported similar issues with complex RTOS scenarios on Renode

Questions

1. Are there known issues with running Zephyr kernel on nRF52840 in Renode simulation?
2. Are there recommended workarounds or simulation configuration adjustments?
3. What is the expected level of Renode support for nRF52840 with full Zephyr kernel?
4. Should this be reported to the Renode project instead, or is this a Zephyr-side configuration issue?
5. Are there alternative simulation approaches that work better for nRF52840/Zephyr development?

Request

I am looking for:

• Updated guidance on Renode + nRF52840 + Zephyr compatibility
• Known workarounds for these simulation issues
• Confirmation whether this is a Renode limitation or Zephyr configuration issue
• Recommendations for alternative development/testing approaches

Any help or insights from the community would be greatly appreciated. If additional logs, configurations, or test cases would be helpful, I'm happy to provide them.

Thank you!