diff --git a/cmake/modules/RootConfiguration.cmake b/cmake/modules/RootConfiguration.cmake
index 7055457189e9d..dd73530daa6fd 100644
--- a/cmake/modules/RootConfiguration.cmake
+++ b/cmake/modules/RootConfiguration.cmake
@@ -434,26 +434,24 @@ if(qt6web)
 else()
   set(hasqt6webengine undef)
 endif()
-if (tmva-cpu)
-  set(hastmvacpu define)
-else()
-  set(hastmvacpu undef)
-endif()
-if (tmva-gpu)
-  set(hastmvagpu define)
-else()
-  set(hastmvagpu undef)
-endif()
-if (tmva-cudnn)
-   set(hastmvacudnn define)
-else()
-   set(hastmvacudnn undef)
-endif()
-if (tmva-pymva)
-  set(haspymva define)
-else()
-  set(haspymva undef)
-endif()
+set(hastmvacpu undef)
+set(hastmvagpu undef)
+set(hastmvacudnn undef)
+set(haspymva undef)
+if(tmva)
+  if (tmva-cpu)
+    set(hastmvacpu define)
+  endif()
+  if (tmva-gpu)
+    set(hastmvagpu define)
+  endif()
+  if (tmva-cudnn)
+     set(hastmvacudnn define)
+  endif()
+  if (tmva-pymva)
+    set(haspymva define)
+  endif()
+endif(tmva)
 if (uring)
   set(hasuring define)
 else()
diff --git a/cmake/modules/SearchInstalledSoftware.cmake b/cmake/modules/SearchInstalledSoftware.cmake
index 71b257e95ea7e..1d05b239ada17 100644
--- a/cmake/modules/SearchInstalledSoftware.cmake
+++ b/cmake/modules/SearchInstalledSoftware.cmake
@@ -1016,6 +1016,8 @@ if(tmva)
         message(SEND_ERROR "cudnn not found  while -Dtmva-cudnn=ON. Install it on the system, or disable option 'tmva-cudnn'")
       endif()
     endif()
+  else()
+    set(tmva-cudnn OFF CACHE BOOL "Disabled because 'tmva-gpu' unavailable (${tmva-cudnn_description})" FORCE)
   endif()
   if(tmva-pymva)
     if(NOT Python3_NumPy_FOUND OR NOT Python3_Development_FOUND)
diff --git a/test/PostInstall/check-headers.sh b/test/PostInstall/check-headers.sh
index 98122e5600872..a4999f0196483 100644
--- a/test/PostInstall/check-headers.sh
+++ b/test/PostInstall/check-headers.sh
@@ -28,19 +28,17 @@ fi
 
 
 # Check all installed headers for include errors. Some headers cannot be used standalone:
-suppressions="TMVA\|vdt"							# External
-suppressions+="\|RField[A-Z]\|RtypesImp.h\|TAtomicCount[A-Z]\|CladDerivator.h\|TBranchProxyTemplate"	# Not to be used standalone
+suppressions="RField[A-Z]\|RtypesImp.h\|TAtomicCount[A-Z]\|CladDerivator.h\|TBranchProxyTemplate"	# Not to be used standalone
 suppressions+="\|TWin32"							# Why are these installed in Linux?
 suppressions+="\|xRooHypoSpace.h\|xRooFit"					# Uses macros to declare namespaces
-suppressions+="\|RDaos.h"							# Might not be installed
 suppressions+="\|RIoUring.hxx"							# Might not be installed
+suppressions+="\|TCudnn.h"							# Might not be installed
 suppressions+="\|CPyCppyy/DispatchPtr.h\|CPyCppyy/API.h"			# Would need to include Python.h
 suppressions+="\|/bvh"								# Includes a non-functioning std::span in c++17
 suppressions+="\|cfortran.h"							# Seems unable to run with modern compilers
 suppressions+="\|hipSYCL.h\|GenVectorX"						# Unconditionally installed on Fedora/Ubuntu even if broken
 suppressions+="\|TR[A-Z].*__ctors.h"						# R interface without any includes, so cannot be parsed as C++
 suppressions+="\|RTaskArena.hxx\|TThreadExecutor.hxx\|TTreeProcessorMT.hxx"	# Will raise errors if imt=Off
-
 HEADERS=$(find "${INCLUDE_DIR}" -type f -name '*.h*' | grep -v "${suppressions}")
 
 xargs -P ${NCPU:-1} -n 1 "${CXX}" -fsyntax-only -x c++ -std=c++${CXXSTANDARD} ${CXXFLAGS} -I"${INCLUDE_DIR}" <<< "${HEADERS}"
diff --git a/tmva/tmva/inc/TMVA/DNN/Architectures/Cpu/CpuTensor.h b/tmva/tmva/inc/TMVA/DNN/Architectures/Cpu/CpuTensor.h
index b5559d0146de7..f0b6c5b95fa6a 100644
--- a/tmva/tmva/inc/TMVA/DNN/Architectures/Cpu/CpuTensor.h
+++ b/tmva/tmva/inc/TMVA/DNN/Architectures/Cpu/CpuTensor.h
@@ -18,7 +18,7 @@
 #define TMVA_DNN_ARCHITECTURES_CPU_CPUTENSOR
 
 #include <cstddef>
-
+#include <iostream>
 
 #include "TMatrix.h"
 #include "TMVA/Config.h"
diff --git a/tmva/tmva/inc/TMVA/DNN/RNN/GRULayer.h b/tmva/tmva/inc/TMVA/DNN/RNN/GRULayer.h
index 33a01754dfc34..8f79bf42b5b3b 100644
--- a/tmva/tmva/inc/TMVA/DNN/RNN/GRULayer.h
+++ b/tmva/tmva/inc/TMVA/DNN/RNN/GRULayer.h
@@ -35,7 +35,9 @@
 #include <vector>
 
 #include "TMatrix.h"
+#include "TMVA/DNN/GeneralLayer.h"
 #include "TMVA/DNN/Functions.h"
+#include "TMVA/DNN/CNN/ContextHandles.h"
 
 namespace TMVA
 {
diff --git a/tmva/tmva/inc/TMVA/DNN/RNN/LSTMLayer.h b/tmva/tmva/inc/TMVA/DNN/RNN/LSTMLayer.h
index 16e6df15d9829..9cf42e258269f 100644
--- a/tmva/tmva/inc/TMVA/DNN/RNN/LSTMLayer.h
+++ b/tmva/tmva/inc/TMVA/DNN/RNN/LSTMLayer.h
@@ -35,7 +35,9 @@
 #include <vector>
 
 #include "TMatrix.h"
+#include "TMVA/DNN/GeneralLayer.h"
 #include "TMVA/DNN/Functions.h"
+#include "TMVA/DNN/CNN/ContextHandles.h"
 
 namespace TMVA
 {
diff --git a/tmva/tmva/inc/TMVA/DNN/RNN/RNNLayer.h b/tmva/tmva/inc/TMVA/DNN/RNN/RNNLayer.h
index 3eb10083ed9cb..3d9a121e98185 100644
--- a/tmva/tmva/inc/TMVA/DNN/RNN/RNNLayer.h
+++ b/tmva/tmva/inc/TMVA/DNN/RNN/RNNLayer.h
@@ -35,7 +35,9 @@
 #include <string>
 
 #include "TMatrix.h"
+#include "TMVA/DNN/GeneralLayer.h"
 #include "TMVA/DNN/Functions.h"
+#include "TMVA/DNN/CNN/ContextHandles.h"
 
 namespace TMVA
 {