diff --git a/src/control/cam_comp.F90 b/src/control/cam_comp.F90
index 7667b584..27fd57a7 100644
--- a/src/control/cam_comp.F90
+++ b/src/control/cam_comp.F90
@@ -152,7 +152,7 @@ subroutine cam_init(caseid, ctitle, model_doi_url,                         &
       dtime_phys = 0.0_r8
       call mark_as_initialized('timestep_for_physics')
 
-      is_first_timestep = is_first_step()
+      is_first_timestep = .true.
       call mark_as_initialized('is_first_timestep')
 
       call init_pio_subsystem()
diff --git a/src/data/air_composition.F90 b/src/data/air_composition.F90
index 0da0a5b2..43ce33d0 100644
--- a/src/data/air_composition.F90
+++ b/src/data/air_composition.F90
@@ -16,6 +16,7 @@ module air_composition
    public  :: air_composition_init
    public  :: dry_air_composition_update
    public  :: water_composition_update
+
    ! get_cp_dry: (generalized) heat capacity for dry air
    public :: get_cp_dry
    ! get_cp: (generalized) heat capacity
@@ -533,7 +534,7 @@ subroutine dry_air_composition_update(mmr, ncol, to_dry_factor)
 
       cappav(:ncol,:) = rairv(:ncol,:) / cpairv(:ncol,:)
 
-   end subroutine air_composition_update
+   end subroutine dry_air_composition_update
 
    !===========================================================================
    !---------------------------------------------------------------------------
@@ -557,12 +558,19 @@ subroutine water_composition_update(mmr, ncol, vcoord, to_dry_factor)
          ! FV: moist pressure vertical coordinate does not need update.
       else if (vcoord == vc_dry_pressure) then
          ! SE
+
+         ! TODO hplin 9/17/24: for compatibility with CAM-SIMA that allocates thermodynamic_active_species_idx(0:num_advected)
+         ! (whereas CAM only allocates 1-indexed) I subset it here. But from the meaning of the code arguments
+         ! it is unknown where it was meant to be thermodynamic_active_species_idx_dycore.
+         ! This should be verified during code review.
          call get_cp(mmr(:ncol,:,:), .false., cp_or_cv_dycore(:ncol,:), &
-                     factor=to_dry_factor, active_species_idx_dycore=thermodynamic_active_species_idx, &
+                     factor=to_dry_factor, active_species_idx_dycore=thermodynamic_active_species_idx(1:), &
                      cpdry=cpairv(:ncol,:))
       else if (vcoord == vc_height) then
          ! MPAS
-         call get_R(mmr(:ncol,:,:), thermodynamic_active_species_idx, &
+
+         ! TODO hplin 9/17/24 same here.
+         call get_R(mmr(:ncol,:,:), thermodynamic_active_species_idx(1:), &
                     cp_or_cv_dycore(:ncol,:), fact=to_dry_factor, Rdry=rairv(:ncol,:))
 
          ! internal energy coefficient for MPAS
diff --git a/src/data/cam_thermo.F90 b/src/data/cam_thermo.F90
index 2b0af969..2c7f62a5 100644
--- a/src/data/cam_thermo.F90
+++ b/src/data/cam_thermo.F90
@@ -220,7 +220,7 @@ end subroutine cam_thermo_init
    subroutine cam_thermo_dry_air_update(mmr, T, ncol, update_thermo_variables, to_dry_factor)
       use air_composition, only: dry_air_composition_update
       use air_composition, only: update_zvirv
-      use string_utils,    only: int2str
+      use string_utils,    only: to_str
 
       real(kind_phys),    intent(in) :: mmr(:,:,:) ! constituents array (mmr = dry mixing ratio, if not use to_dry_factor to convert)
       real(kind_phys),    intent(in) :: T(:,:)     ! temperature
@@ -1579,6 +1579,7 @@ subroutine get_hydrostatic_energy_1hd(tracer, moist_mixing_ratio, pdel_in, &
       use cam_logfile,     only: iulog
       use dyn_tests_utils, only: vc_height, vc_moist_pressure, vc_dry_pressure
       use air_composition, only: wv_idx
+      use air_composition, only: dry_air_species_num
       use physconst,       only: rga, latvap, latice
 
       ! Dummy arguments
diff --git a/src/data/registry.xml b/src/data/registry.xml
index e55e8a4c..de0c7439 100644
--- a/src/data/registry.xml
+++ b/src/data/registry.xml
@@ -16,6 +16,7 @@
   <metadata_file>$SRCROOT/src/data/ref_pres.meta</metadata_file>
   <metadata_file>$SRCROOT/src/dynamics/utils/vert_coord.meta</metadata_file>
   <metadata_file>$SRCROOT/src/dynamics/utils/hycoef.meta</metadata_file>
+  <metadata_file>$SRCROOT/src/dynamics/tests/dyn_tests_utils.meta</metadata_file>
   <!-- Variables registered to physics_types -->
   <file name="physics_types" type="module">
     <use module="ccpp_kinds" reference="kind_phys"/>
@@ -254,7 +255,7 @@
     <!-- Timestep properties -->
     <variable local_name="is_first_timestep"
               standard_name="is_first_timestep"
-              units="flag" type="logical" access="protected">
+              units="flag" type="logical">
       <long_name>flag indicating if is first timestep of initial run</long_name>
     </variable>
     <!-- State tendencies -->
@@ -422,8 +423,8 @@
       <initial_value>zvir</initial_value>
     </variable>
     <variable local_name="cp_or_cv_dycore"
-              standard_name="enthalpy_or_internal_energy_scaling_factor_for_energy_consistency?"
-              units="1" type="real" kind="kind_phys"
+              standard_name="enthalpy_or_internal_energy_scaling_factor_for_energy_consistency_tbd"
+              units="J kg-1 K-1" type="real" kind="kind_phys"
               allocatable="allocatable">
       <long_name>Enthalpy or internal energy scaling factor for energy consistency</long_name>
       <dimensions>horizontal_dimension vertical_layer_dimension</dimensions>
diff --git a/src/dynamics/tests/dyn_tests_utils.meta b/src/dynamics/tests/dyn_tests_utils.meta
index 91f30f6d..d236ec6f 100644
--- a/src/dynamics/tests/dyn_tests_utils.meta
+++ b/src/dynamics/tests/dyn_tests_utils.meta
@@ -6,12 +6,12 @@
   name  = dyn_tests_utils
   type  = module
 [ vc_dycore ]
-  standard_name = vertical_coordinate_for_dynamical_core?
-  units = none
+  standard_name = vertical_coordinate_for_dynamical_core_tbd
+  units = 1
   type = integer
   dimensions = ()
 [ vc_physics ]
-  standard_name = vertical_coordinate_for_physics?
-  units = none
+  standard_name = vertical_coordinate_for_physics_tbd
+  units = 1
   type = integer
   dimensions = ()
diff --git a/src/dynamics/utils/dyn_thermo.F90 b/src/dynamics/utils/dyn_thermo.F90
index c4c4723c..9b465031 100644
--- a/src/dynamics/utils/dyn_thermo.F90
+++ b/src/dynamics/utils/dyn_thermo.F90
@@ -61,7 +61,7 @@ subroutine get_cp(tracer,inv_cp,cp,dp_dry,active_species_idx_dycore)
       !Declare local variables:
       real(kind_phys), allocatable :: tracer_phys(:,:,:,:)
       real(kind_phys), allocatable :: cp_phys(:,:,:)
-      real(kind_phys), allocatable :: dp_dry_phys(:,:,:)
+      real(kind_phys), allocatable :: factor_phys(:,:,:)
 
       !check_allocate variables:
       integer :: iret !allocate status integer
@@ -70,11 +70,16 @@ subroutine get_cp(tracer,inv_cp,cp,dp_dry,active_species_idx_dycore)
       !Check if kinds are different:
       if (kind_phys == kind_dyn) then
 
-         !The dynamics and physics kind is the same, so just call the physics
-         !routine directly:
-         call get_cp_phys(tracer,inv_cp,cp, &
-                          dp_dry=dp_dry, &
-                          active_species_idx_dycore=active_species_idx_dycore)
+         ! The dynamics and physics kind is the same, so just call the physics
+         ! routine directly:
+         if(present(dp_dry)) then
+            call get_cp_phys(tracer,inv_cp,cp, &
+                             factor=1.0_kind_phys/dp_dry, &
+                             active_species_idx_dycore=active_species_idx_dycore)
+         else
+            call get_cp_phys(tracer,inv_cp,cp, &
+                             active_species_idx_dycore=active_species_idx_dycore)
+         endif
 
       else
 
@@ -95,18 +100,18 @@ subroutine get_cp(tracer,inv_cp,cp,dp_dry,active_species_idx_dycore)
 
          !Allocate and set optional variables:
          if (present(dp_dry)) then
-            allocate(dp_dry_phys(size(dp_dry, 1), size(dp_dry, 2), size(dp_dry,3)), stat=iret)
+            allocate(factor_phys(size(dp_dry, 1), size(dp_dry, 2), size(dp_dry,3)), stat=iret)
             call check_allocate(iret, subname, &
-                                'dp_dry_phys', &
+                                'factor_phys', &
                                 file=__FILE__, line=__LINE__)
 
             !Set optional local variable:
-            dp_dry_phys = real(dp_dry, kind_phys)
+            factor_phys = 1.0_kind_phys/real(dp_dry, kind_phys)
          end if
 
-         !Call physics routine using local vriables with matching kinds:
+         !Call physics routine using local variables with matching kinds:
          call get_cp_phys(tracer_phys,inv_cp,cp_phys, &
-                          dp_dry=dp_dry_phys, &
+                          factor=factor_phys, &
                           active_species_idx_dycore=active_species_idx_dycore)
 
          !Set output variables back to dynamics kind:
@@ -116,8 +121,8 @@ subroutine get_cp(tracer,inv_cp,cp,dp_dry,active_species_idx_dycore)
          deallocate(tracer_phys)
          deallocate(cp_phys)
 
-         if (allocated(dp_dry_phys)) then
-            deallocate(dp_dry_phys)
+         if (allocated(factor_phys)) then
+            deallocate(factor_phys)
          end if
 
 
@@ -957,7 +962,7 @@ subroutine get_rho_dry(tracer,temp,ptop,dp_dry,tracer_mass,&
 
          end if
 
-         !Call physics routine using local vriables with matching kinds:
+         !Call physics routine using local variables with matching kinds:
          call get_rho_dry_phys(tracer_phys,temp_phys, &
                                ptop_phys, dp_dry_phys,tracer_mass, &
                                rho_dry=rho_dry_phys, &