How to find problem in design after compiliation / fitter failure

It turns out that Terasic does not use the board_spec.xml file for generating their BSP, hence the wrong values. They instead modify the .dts file directly to generate the device tree / .dtb file. Unfortunately I could not get a reply on how to correctly set the parameters for the board_spec.xml file to make the HTML report more accurate. I am now using these values:

File hld/share/models/dm/5csema5f31c6_dm.xml:

<!-- Device model for: 5CSEMA5F31C6 -->
<device_model version="0.9" target_model="cyclonev_tm.xml">
  <fmax expected="200" min="100" high="175"/>
  <resources>
    <alms num="32070"/>
    <ffs num="128280"/>
    <dsps num="87"/><!-- variable precision DSP blocks -->
    <rams num="3970"/><!-- M10Ks -->
  </resources>
</device_model>

For the number of FFs I guessed it should be four times the number of ALMs. The values for fmax-{expected, min, high} are from the reference kit and I have no idea if these are close-enough values... The resource estimate is much closer to reality now.

To use the file above, I had to replace

  <device device_model="5csxfc6d6f31c8es_dm.xml">

with

  <device device_model="5csema5f31c6_dm.xml">

in the board_spec.xml file.