diff --git a/tools/bench/guix-channels.scm b/tools/bench/guix-channels.scm
new file mode 100644
index 0000000000000000000000000000000000000000..25eb5c93a65d9e1a7fad7e706eccb0227b50d72f
--- /dev/null
+++ b/tools/bench/guix-channels.scm
@@ -0,0 +1,45 @@
+(list (channel
+        (name 'guix)
+        (url "https://git.savannah.gnu.org/git/guix.git")
+        (branch "master")
+        (commit
+          "842e491e2e798298246f3449b39d1e3f36fe7d1c")
+        (introduction
+          (make-channel-introduction
+            "9edb3f66fd807b096b48283debdcddccfea34bad"
+            (openpgp-fingerprint
+              "BBB0 2DDF 2CEA F6A8 0D1D  E643 A2A0 6DF2 A33A 54FA"))))
+      (channel
+        (name 'guix-hpc-non-free)
+        (url "https://gitlab.inria.fr/guix-hpc/guix-hpc-non-free.git")
+        (branch "master")
+        (commit
+          "c91f254c22f6ae467a7eda65a660d0ae1f0b690a"))
+      (channel
+        (name 'guix-science-nonfree)
+        (url "https://github.com/guix-science/guix-science-nonfree.git")
+        (branch "master")
+        (commit
+          "9a3f3824d8ed289832d706679410edadac1202ae")
+        (introduction
+          (make-channel-introduction
+            "58661b110325fd5d9b40e6f0177cc486a615817e"
+            (openpgp-fingerprint
+              "CA4F 8CF4 37D7 478F DA05  5FD4 4213 7701 1A37 8446"))))
+      (channel
+        (name 'guix-past)
+        (url "https://gitlab.inria.fr/guix-hpc/guix-past")
+        (branch "master")
+        (commit
+          "1e25b23faa6b1716deaf7e1782becb5da6855942")
+        (introduction
+          (make-channel-introduction
+            "0c119db2ea86a389769f4d2b9c6f5c41c027e336"
+            (openpgp-fingerprint
+              "3CE4 6455 8A84 FDC6 9DB4  0CFB 090B 1199 3D9A EBB5"))))
+      (channel
+        (name 'guix-hpc)
+        (url "https://gitlab.inria.fr/guix-hpc/guix-hpc.git")
+        (branch "master")
+        (commit
+          "674bc362dea0b233eb84d79d36e25460907afd7a")))
diff --git a/tools/bench/plafrim/run.sh b/tools/bench/plafrim/run.sh
index 55ca0278540885f5434ecb0c62634dbdc3bbb1b6..a9514a1e43b9795f63e3fcbf526305215795eecd 100755
--- a/tools/bench/plafrim/run.sh
+++ b/tools/bench/plafrim/run.sh
@@ -21,7 +21,7 @@ unset STARPU_WORKERS_NOBIND
 export XDG_CACHE_HOME=/tmp/guix-$$
 
 # save guix commits
-guix describe --format=json > guix.json
+guix time-machine -C ./tools/bench/guix-channels.scm -- describe --format=json > guix.json
 
 # define env var depending on the node type
 if [ $NODE = "bora" ]
@@ -61,24 +61,24 @@ else
   echo "$0: Please set the MPI environnement variable to openmpi or nmad."
   exit -1
 fi
-GUIX_ADHOC="coreutils gawk grep hwloc jube perl python python-click python-certifi python-elasticsearch python-gitpython python-matplotlib python-pandas python-seaborn r-ggplot2 r-plyr r-reshape2 sed slurm mkl@2019.1.144"
+GUIX_ADHOC="coreutils gawk grep hwloc jube perl python python-click python-certifi python-elasticsearch python-gitpython python-matplotlib python-pandas python-seaborn r-ggplot2 r-plyr r-reshape2 sed slurm@22 mkl@2019"
 GUIX_RULE="-D $GUIX_ENV $GUIX_ENV_MPI $GUIX_ADHOC $GUIX_ADHOC_MPI"
 
 # Submit jobs
 
 # OpenMPI version
-exec guix shell --pure \
-                --preserve=PLATFORM \
-                --preserve=NODE \
-                --preserve=LD_PRELOAD \
-                --preserve=^CI \
-                --preserve=^SLURM \
-                --preserve=^JUBE \
-                --preserve=^MPI \
-                --preserve=^STARPU \
-                --preserve=^CHAMELEON \
-                $GUIX_RULE \
-                -- /bin/bash --norc ./tools/bench/plafrim/slurm.sh
+exec guix time-machine -C ./tools/bench/guix-channels.scm -- shell --pure \
+       --preserve=PLATFORM \
+       --preserve=NODE \
+       --preserve=LD_PRELOAD \
+       --preserve=^CI \
+       --preserve=^SLURM \
+       --preserve=^JUBE \
+       --preserve=^MPI \
+       --preserve=^STARPU \
+       --preserve=^CHAMELEON \
+       $GUIX_RULE \
+       -- /bin/bash --norc ./tools/bench/plafrim/slurm.sh
 
 echo "####################### End Chameleon benchmarks #######################"
 
diff --git a/tools/check_header.sh b/tools/check_header.sh
index e2ac2b32823ee4f8a05de2431cd78167c761ed3f..a1e96c594f2902023c2b4bd7b168d1dc92bc7c64 100755
--- a/tools/check_header.sh
+++ b/tools/check_header.sh
@@ -192,7 +192,8 @@ files=$( git ls-files                     |
              grep -v "input/.*\.in"       |
              grep -v "distrib/debian/.*"  |
              grep -v "tools/bench/jube/requirements.txt" |
-             grep -v "\.org"              )
+             grep -v "\.org"              |
+             grep -v "\.scm" )
 if [ $# -gt 0 ]
 then
     files=$*