diff --git a/Doc/user_guide.tex b/Doc/user_guide.tex
index 6f814a422..a42020081 100644
--- a/Doc/user_guide.tex
+++ b/Doc/user_guide.tex
@@ -645,11 +645,10 @@ available:\\
                                   & CUDA Toolkit installed on the workstation \\
                                   & or available on the compute nodes of the HPC facility.\\
 \texttt{--with-cuda-mpi=value}    & enable usage of a CUDA-aware MPI library (default: no).\\
-\end{tabular}{ll}
+\end{tabular}
 
-To modify or extend \configure, see the Wiki pages on GitLab:
-\texttt{https://gitlab.com/QEF/q-e/-/wikis}.
-For advanced users only!
+To modify or extend \configure\ (advanced users only!), see the Wiki pages
+on GitLab: \texttt{https://gitlab.com/QEF/q-e/-/wikis}.
 
 \subsubsection{Manual configuration}
 \label{SubSec:manconf}
@@ -665,7 +664,8 @@ if you want to link internal FFTW). For a correct choice of preprocessing
 flags, refer to the documentation in \texttt{include/defs.h.README}.
 
 Even if \configure\ works, you may need to tweak the \texttt{make.inc}
-file. It is very simple, but please note that if you change any settings
+file. It is very simple, but please note that a) you must know what you are
+doing, and b) if you change any settings
 (e.g. preprocessing, compilation flags)
 after a previous, successful or failed, compilation, you must run
 \texttt{make clean} before recompiling, unless you know exactly which
@@ -676,7 +676,7 @@ unless you use option \texttt{--save}.
 \subsection{Libraries}
 \label{Sec:Libraries}
 
-\qe\ contains a copy of some needed external libraries:
+\qe\ downloads a copy of the following external libraries if needed:
 \begin{itemize}
  \item FoX for reading and writing xml files;
  \item BLAS (\texttt{http://www.netlib.org/blas/}) and LAPACK
diff --git a/README.md b/README.md
index 73dd855cb..8dadef910 100644
--- a/README.md
+++ b/README.md
@@ -7,8 +7,10 @@ Optimization)
 [![License: GPL v2](https://img.shields.io/badge/License-GPL%20v2-blue.svg)](https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html)
 
 ## USAGE
-Quick installation instructions for the impatient. Go to the directory 
-where this file is. Using "make"
+Quick installation instructions for CPU-based machines. For GPU execution, see
+file [README_GPU.md](README_GPU.md). Go to the directory where this file is. 
+
+Using "make"
 (`[]` means "optional"):
 ```
 ./configure [options]
@@ -35,7 +37,8 @@ is prepended onto all install directories.
 
 For more information, see the general documentation in directory Doc/, 
 package-specific documentation in \*/Doc/, and the web site 
-http://www.quantum-espresso.org/. Documentation for developers 
+http://www.quantum-espresso.org/. Technical documentation for users and
+developers 
 can be found on [Wiki page on gitlab](https://gitlab.com/QEF/q-e/-/wikis/home).
 
 ## PACKAGES
@@ -62,9 +65,6 @@ The following libraries have been isolated and partially encapsulated in view of
 - LRlib: performs a variety of tasks connected with (time-dependent) DFPT, to be used also in connection with Many-Body Perturbation Theory.
 - upflib: pseudopotential-related code.
 
-## GPU-enabled version
-Since Feb.2021 this repository also works for GPU's (currently only NVIDIA). See file [README_GPU.md](README_GPU.md).
-
 ## Contributing
 Quantum ESPRESSO is an open project: contributions are welcome.
 Read the [Contribution Guidelines](CONTRIBUTING.md) to see how you
diff --git a/UtilXlib/mp.f90 b/UtilXlib/mp.f90
index b2def3f8d..facf9edca 100644
--- a/UtilXlib/mp.f90
+++ b/UtilXlib/mp.f90
@@ -4839,7 +4839,7 @@ END SUBROUTINE mp_type_free
 #if  defined(__GPU_MPI)
         msglen = size(msg_d)
         ierr = cudaDeviceSynchronize()            ! This syncs __GPU_MPI
-        CALL reduce_base_real_to_gpu( 2 * msglen, msg_d, res_h, gid, -1 )
+        CALL reduce_base_real_to_gpu( 2 * msglen, msg_d, res_d, gid, -1 )
         RETURN ! Sync not needed after MPI call
 #else
         ALLOCATE( msg_h, source=msg_d )           ! This syncs __MPI case