In former versions, the aforementioned image was 'required' to run gem5 although it wasn't actually used at all. With the new python script fail_fs.py, it suffices to start gem5 on a target foo.elf by simply typing $ ../scripts/run-gem5.sh path/to/target/foo.elf Change-Id: I7f48460e50d48d55fe22f2381e2ae8aec8510233