---
title: "Questa Simulation Setup for GeMRTOS Nios V: Two Common Fixes"
description: "Since Quartus Prime version 22, **Questa** has replaced ModelSim as the simulation tool in the Quartus Prime Suite. While NativeLink simulation techniques are the same as ModelSim, two common issues arise when first setting up Questa for GeMRTOS **Nios V**…"
url: "https://rcayssials.hopto.org/gemrtosdocs/questa-issues/"
updated: "2026-06-01"
category: General
tags:
  - Avalon MM
  - GeMRTOS
  - Nios 2
  - Nios V
  - "RISC-V"
---

# Questa Simulation Setup for GeMRTOS Nios V: Two Common Fixes

Since Quartus Prime version 22, **Questa** has replaced ModelSim as the simulation tool in the Quartus Prime Suite. While NativeLink simulation techniques are the same as ModelSim, two common issues arise when first setting up Questa for GeMRTOS **Nios V** FPGA simulation on Windows.

## Issue 1: Questa Requires a License

Questa software requires a valid license to run. At minimum, a temporary free license must be downloaded from Intel before Questa can be launched. Without a license, Questa will refuse to start.

See the [Questa-Intel FPGA Edition license setup guide](/gemrtosdocs/specifying-the-license-for-the-questa-intel-fpga-edition-software/) for step-by-step instructions on configuring the `MGLS_LICENSE_FILE` environment variable and the `mgcld` daemon.

## Issue 2: Signals Not Visible When Simulating a Nios Eclipse Project

When simulating a Nios II/V Eclipse project in Questa, signals may not appear in the wave window. To make all signals visible, execute the following commands from the Questa command prompt:

```
do load_sim.tcl.
ld_debug
```

Using `ld_debug` instead of `ld` causes all signals to appear in the simulation.

## Key Takeaways

- Questa replaced ModelSim in **Quartus Prime 22+** — existing NativeLink simulation flows carry over, but a license is now required even for basic simulation.
- Download a free temporary license from Intel and configure **`MGLS_LICENSE_FILE`** before launching Questa for GeMRTOS Nios V simulations.
- If signals are missing in Questa after loading a Nios Eclipse project simulation, run **`ld_debug`** instead of `ld` to expose all signals in the wave window.

**Reference:** [Intel Community — Nios II simulation with Questa](https://community.intel.com/t5/Nios-V-II-Embedded-Design-Suite/Nios-II-simulation-with-Questa/m-p/1351656).