diff --git a/macro/beamtime/mcbm2024/README_GeoPar.md b/macro/beamtime/mcbm2024/README_GeoPar.md
index 73a78dec500b05ee40fbffd26368ceec87381557..54ed10a4545cc13d3e9760512fff9d8d4f1f9924 100644
--- a/macro/beamtime/mcbm2024/README_GeoPar.md
+++ b/macro/beamtime/mcbm2024/README_GeoPar.md
@@ -8,7 +8,18 @@
    ```
    ./macro/beamtime/mcbm2024/switch_geo_par.sh
    ```
-1.
+1. Rebasing Cbmroot
+   1. Commit **and push** any local files/changes if you were in "mCBM mode" and did local changes in either the
+      geometry or parameters folders. Otherwise the rebase script will not do anything or they
+   1. Execute the following script. \
+      It relies on the presence of a remote pointing to the offical version (e.g. `origin` or `upstream`) and may ask
+      for some login information when fetching the latest changes depending on your remote definition.
+      ```
+      ./macro/beamtime/mcbm2024/rebase_cbmroot.sh
+      ```
+      Rebasing directly from the CLI without caring about the state of the geo and params folders will fail if they are
+      in  "mCBM mode" and may lead to a broken local copy \
+      => As soon as you start using the `switch_geo_par.sh` script in a Cbmroot copy, rebase it only with this script!!!
 
 # CAVEATS
 
@@ -23,6 +34,10 @@
    versions" \
    => Switching to another branch or a different detached commit than the "official version" will confuse them \
    => This in turn has high chances to lead to broken copies of the `geometry` and/or `parameters` folders
+1. **All these scripts apart from the one to commit changes will work only on clean copies!!!** \
+   => local changes have to be either committed or deleted/reverted before using them!!! \
+   => This also means that the scripts will all switch to the latest remote version. So doing "mcbm > official > mcbm"
+      may lead to a different commit! And local commits which are not yet pushed may be lost!
 1. Space needed:
    - around `100 MB` for geometries
    - around `1.6 GB` for parameters
diff --git a/macro/beamtime/mcbm2024/rebase_cbmroot.sh b/macro/beamtime/mcbm2024/rebase_cbmroot.sh
new file mode 100755
index 0000000000000000000000000000000000000000..b2a2201cef3316abdaf1f8c528b8aff5c4023328
--- /dev/null
+++ b/macro/beamtime/mcbm2024/rebase_cbmroot.sh
@@ -0,0 +1,55 @@
+#!/bin/bash
+# Copyright (C) 2024 GSI Helmholtzzentrum fuer Schwerionenforschung, Darmstadt
+# SPDX-License-Identifier: GPL-3.0-only
+# First commited by Pierre-Alain Loizeau
+
+WAS_MCBM_MODE=0
+START_DIR=$PWD
+
+# I: switch of branch/commit. Done only after all checks to avoid Geometry and Parameter folder going out of sync
+#     (one in "Official detached commit" and the other on "mCBM repo HEAD" mode)
+# I-A: Geometry folder
+# I-A-1) Go to folder
+cd ${VMCWORKDIR}/geometry
+# I-A-2) Check if current version is the Official detached commit or the mCBM repo HEAD
+if [[ 1 -eq $(git status | grep -c "HEAD detached at") ]]; then
+  echo "Geometry folder already in official version, no need to switch back"
+else
+  WAS_MCBM_MODE=1
+  if ! ${VMCWORKDIR}/macro/beamtime/mcbm2024/switch_geo_par.sh; then
+    echo "Failed switching the geometry and parameters folders back to the official version, stopping there"
+    exit 1
+  fi
+fi
+# I-B: parameters folder
+# I-B-1) Go to folder
+cd ${VMCWORKDIR}/parameters
+# I-B-2) Check if current version is the Official detached commit or the mCBM repo HEAD
+if [[ 1 -eq $(git status | grep -c "HEAD detached at") ]]; then
+  echo "Parameters folder already in official version, no need to switch back"
+else
+  echo "Check on geometry folder should have already reverted the parameters one but still in mCBM mode"
+  echo "Please check your local folders with git status, your copy may be brocken/have folders out of sync"
+  exit 2
+fi
+
+cd $START_DIR
+
+# II: Cbmroot update in the standard way,
+#     => assumes in the source root folder but should anyway work anywhere in the tree
+#     => assumes that the official repo remote is already defined (e.g. either as origin or upstream)
+official=$(git remote -v | grep fetch | grep "computing/cbmroot.git" | cut -f1)
+if [ -n "${official}" ]; then
+  # Depending on your remote settings, the next command may ask for login/password information
+  git fetch ${official}
+  git rebase ${official}/master
+else
+  echo "No remote found pointing to the official cbmroot repository/fork, rebase will not be done!!!!"
+fi
+
+# III: revert geometry and parameters folders to mCBM mode if was the case before this call
+if [[ 1 -eq ${WAS_MCBM_MODE} ]]; then
+  ${VMCWORKDIR}/macro/beamtime/mcbm2024/switch_geo_par.sh
+fi
+
+exit 0