diff --git a/packages/h5hut/package.py b/packages/h5hut/package.py
index 956f547..f8253a7 100644
--- a/packages/h5hut/package.py
+++ b/packages/h5hut/package.py
@@ -5,9 +5,70 @@
 
 
 from spack.package import *
-from spack.pkg.builtin.h5hut import H5hut as SpackH5hut
 
 
-class H5hut(SpackH5hut):
+class H5hut(AutotoolsPackage):
+    """H5hut (HDF5 Utility Toolkit).
+    High-Performance I/O Library for Particle-based Simulations."""
+
+    homepage = "https://amas.psi.ch/H5hut/"
+    url = "https://amas.web.psi.ch/Downloads/H5hut/H5hut-2.0.0rc3.tar.gz"
+    git = "https://gitlab.psi.ch/H5hut/src.git"
 
     version("2.0.0rc6", sha256="980a5c634877265bd3a862fbd439d973d44be9c1d2f840c3635e8c6375d62d7e")
+    version("2.0.0rc3", sha256="1ca9a9478a99e1811ecbca3c02cc49258050d339ffb1a170006eab4ab2a01790")
+
+    version("master", branch="master")
+
+    variant("fortran", default=True, description="Enable Fortran support")
+    variant("mpi", default=True, description="Enable MPI support")
+
+    depends_on("autoconf", type="build", when="build_system=autotools")
+    depends_on("automake", type="build", when="build_system=autotools")
+    depends_on("libtool", type="build", when="build_system=autotools")
+
+    depends_on("mpi", when="+mpi")
+    # h5hut +mpi uses the obsolete function H5Pset_fapl_mpiposix:
+    depends_on("hdf5@1.8:+mpi", when="+mpi")
+    depends_on("hdf5@1.8:", when="~mpi")
+
+    # If built in parallel, the following error message occurs:
+    # install: .libs/libH5hut.a: No such file or directory
+    parallel = False
+
+    @run_before("configure")
+    def validate(self):
+        """Checks if Fortran compiler is available."""
+
+        if "+fortran" in self.spec and not self.compiler.fc:
+            raise RuntimeError("Cannot build Fortran variant without a Fortran compiler.")
+
+    def flag_handler(self, name, flags):
+        build_system_flags = []
+        if name == "cflags" and self.spec.version < Version("2.0.0rc7"):
+            build_system_flags = ["-DH5_USE_110_API"]
+        return flags, None, build_system_flags
+
+    def autoreconf(self, spec, prefix):
+        which("bash")("autogen.sh")
+
+    def configure_args(self):
+        spec = self.spec
+        config_args = ["--enable-shared"]
+
+        if "+fortran" in spec:
+            config_args.append("--enable-fortran")
+
+        if "+mpi" in spec:
+            config_args.extend(
+                [
+                    "--enable-parallel",
+                    "CC={0}".format(spec["mpi"].mpicc),
+                    "CXX={0}".format(spec["mpi"].mpicxx),
+                ]
+            )
+
+            if "+fortran" in spec:
+                config_args.append("FC={0}".format(spec["mpi"].mpifc))
+
+        return config_args
diff --git a/packages/opal-x/package.py b/packages/opal-x/package.py
index 5615dcc..53688c6 100644
--- a/packages/opal-x/package.py
+++ b/packages/opal-x/package.py
@@ -54,9 +54,10 @@ class OpalX(CMakePackage, CudaPackage):
     depends_on("blas")
     depends_on("boost@1.82.0+mpi+chrono+filesystem+iostreams+regex+serialization+system+timer+python+shared")
     depends_on("cmake@3.25.2:", type="build")
-    depends_on("fftw@3.3.10")
+    depends_on("fftw@3.3.10 +mpi")
     depends_on("gsl@2.7+shared")
     depends_on("gnutls@3.5.19:")
+    depends_on("cuda@12.4.0:")
 
     depends_on("h5hut+mpi", when="+mpi")
 
@@ -89,7 +90,7 @@ class OpalX(CMakePackage, CudaPackage):
         ]
 
         if '+cuda' in self.spec:
-            args.append("-DIPPL_PLATFORMS=cuda")
+            args.append("-DIPPL_PLATFORMS=CUDA")
         else:
             args.append("-DIPPL_PLATFORMS=openmp")