diff --git a/src/hydro/PressureEnergy/hydro.h b/src/hydro/PressureEnergy/hydro.h
index a6ca8ba76dc945b772f15aa6fd88308c4192fc23..49dc43a9073d8ea903eec7f2d3611da213b103e5 100644
--- a/src/hydro/PressureEnergy/hydro.h
+++ b/src/hydro/PressureEnergy/hydro.h
@@ -198,6 +198,18 @@ __attribute__((always_inline)) INLINE static float hydro_get_mass(
   return p->mass;
 }
 
+/**
+ * @brief Sets the mass of a particle
+ *
+ * @param p The particle of interest
+ * @param m The mass to set.
+ */
+__attribute__((always_inline)) INLINE static void hydro_set_mass(
+    struct part *restrict p, float m) {
+
+  p->mass = m;
+}
+
 /**
  * @brief Returns the velocities drifted to the current time of a particle.
  *
@@ -233,7 +245,7 @@ __attribute__((always_inline)) INLINE static float hydro_get_internal_energy_dt(
 }
 
 /**
- * @brief Returns the time derivative of internal energy of a particle
+ * @brief Sets the time derivative of internal energy of a particle
  *
  * We assume a constant density.
  *
@@ -245,6 +257,7 @@ __attribute__((always_inline)) INLINE static void hydro_set_internal_energy_dt(
 
   p->u_dt = du_dt;
 }
+
 /**
  * @brief Computes the hydro time-step of a given particle
  *
@@ -525,7 +538,9 @@ __attribute__((always_inline)) INLINE static void hydro_end_force(
  * @param dt_therm The time-step for this kick (for thermodynamic quantities).
  */
 __attribute__((always_inline)) INLINE static void hydro_kick_extra(
-    struct part *restrict p, struct xpart *restrict xp, float dt_therm) {
+    struct part *restrict p, struct xpart *restrict xp, float dt_therm,
+    const struct cosmology *cosmo,
+    const struct hydro_props *restrict hydro_properties) {
 
   /* Do not decrease the energy by more than a factor of 2*/
   if (dt_therm > 0. && p->u_dt * dt_therm < -0.5f * xp->u_full) {
@@ -555,7 +570,8 @@ __attribute__((always_inline)) INLINE static void hydro_kick_extra(
  * @param xp The extended particle to act upon
  */
 __attribute__((always_inline)) INLINE static void hydro_convert_quantities(
-    struct part *restrict p, struct xpart *restrict xp) {
+    struct part *restrict p, struct xpart *restrict xp,
+    const struct cosmology *cosmo) {
 
   /* Compute the pressure */
   const float pressure = gas_pressure_from_internal_energy(p->rho, p->u);
@@ -593,4 +609,21 @@ __attribute__((always_inline)) INLINE static void hydro_first_init_part(
   hydro_init_part(p, NULL);
 }
 
+/**
+ * @brief Overwrite the initial internal energy of a particle.
+ *
+ * Note that in the cases where the thermodynamic variable is not
+ * internal energy but gets converted later, we must overwrite that
+ * field. The conversion to the actual variable happens later after
+ * the initial fake time-step.
+ *
+ * @param p The #part to write to.
+ * @param u_init The new initial internal energy.
+ */
+__attribute__((always_inline)) INLINE static void
+hydro_set_init_internal_energy(struct part *p, float u_init) {
+
+  p->u = u_init;
+}
+
 #endif /* SWIFT_MINIMAL_HYDRO_H */