diff --git a/script/static-checks/common.sh b/script/static-checks/common.sh
deleted file mode 100644
index a2793b7..0000000
--- a/script/static-checks/common.sh
+++ /dev/null
@@ -1,10 +0,0 @@
-#
-# Copyright (c) 2024 Arm Limited. All rights reserved.
-#
-# SPDX-License-Identifier: BSD-3-Clause
-#
-
-function get_merge_base() {
-    git fetch --unshallow origin ${GERRIT_BRANCH#refs/heads/}
-    git merge-base HEAD FETCH_HEAD | head -1
-}
diff --git a/script/static-checks/static-checks-banned-apis.sh b/script/static-checks/static-checks-banned-apis.sh
index 424bbcb..ba10537 100755
--- a/script/static-checks/static-checks-banned-apis.sh
+++ b/script/static-checks/static-checks-banned-apis.sh
@@ -7,10 +7,6 @@
 
 # static-checks-banned-apis.sh <path-to-root-folder> [patch]
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 LOG_FILE=$(mktemp -t banned-api-check.XXXX)
 
 if [[ "$2" == "patch" ]]; then
@@ -43,5 +39,3 @@
 rm -f "$LOG_FILE"
 
 exit "$EXIT_VALUE"
-
-
diff --git a/script/static-checks/static-checks-check-copyright.sh b/script/static-checks/static-checks-check-copyright.sh
index 522bbe8..d80199a 100755
--- a/script/static-checks/static-checks-check-copyright.sh
+++ b/script/static-checks/static-checks-check-copyright.sh
@@ -7,10 +7,6 @@
 
 # test-package-check-copyright.sh DIRECTORY
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 DIRECTORY="$1"
 
 TEST_CASE="Copyright headers of files modified by this patch"
diff --git a/script/static-checks/static-checks-coding-style-line-endings.sh b/script/static-checks/static-checks-coding-style-line-endings.sh
index 8dddace..41bb7c9 100755
--- a/script/static-checks/static-checks-coding-style-line-endings.sh
+++ b/script/static-checks/static-checks-coding-style-line-endings.sh
@@ -5,10 +5,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 TEST_CASE="Line endings are valid"
 
 EXIT_VALUE=0
diff --git a/script/static-checks/static-checks-coding-style.sh b/script/static-checks/static-checks-coding-style.sh
index 9ff51cf..018b926 100755
--- a/script/static-checks/static-checks-coding-style.sh
+++ b/script/static-checks/static-checks-coding-style.sh
@@ -9,10 +9,6 @@
 # against the Linux coding style using the checkpatch.pl script from
 # the Linux kernel source tree.
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 TEST_CASE="Coding style on current patch"
 
 echo "# Check coding style on the last patch"
diff --git a/script/static-checks/static-checks-cpu-erratum-order.sh b/script/static-checks/static-checks-cpu-erratum-order.sh
index 8631c48..e6e32c5 100755
--- a/script/static-checks/static-checks-cpu-erratum-order.sh
+++ b/script/static-checks/static-checks-cpu-erratum-order.sh
@@ -5,9 +5,6 @@
 # SPDX-License-Identifier: BSD-3-Clause
 #
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
 LOG_FILE=$(mktemp -t cpu_workaround_order_check_log.XXXX)
 
 if [[ "$2" == "patch" ]]; then
diff --git a/script/static-checks/static-checks-detect-newly-added-files.sh b/script/static-checks/static-checks-detect-newly-added-files.sh
index 008a147..154e308 100755
--- a/script/static-checks/static-checks-detect-newly-added-files.sh
+++ b/script/static-checks/static-checks-detect-newly-added-files.sh
@@ -11,10 +11,6 @@
 # It runs on every TF-A patch and detects the new files and updates
 # the patch contibutor to include them for Coverity Scan analysis.
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 LOG_FILE=$(mktemp -t files-detection-check.XXXX)
 TFA_PATCH_NEWFILES_LIST=$(mktemp -t tfa-patch-newfiles-list.XXXX)
 EXIT_VALUE=0
diff --git a/script/static-checks/static-checks-include-order.sh b/script/static-checks/static-checks-include-order.sh
index 21fcb72..67c8e4e 100755
--- a/script/static-checks/static-checks-include-order.sh
+++ b/script/static-checks/static-checks-include-order.sh
@@ -7,10 +7,6 @@
 
 # unittest-include-order.sh <path-to-root-folder> [patch]
 
-this_dir="$(readlink -f "$(dirname "$0")")"
-. $this_dir/common.sh
-
-
 LOG_FILE=$(mktemp -t include-order-check.XXXX)
 
 if [[ "$2" == "patch" ]]; then
diff --git a/script/static-checks/static-checks.sh b/script/static-checks/static-checks.sh
index 05747f4..fd022a3 100755
--- a/script/static-checks/static-checks.sh
+++ b/script/static-checks/static-checks.sh
@@ -15,34 +15,12 @@
 export CI_ROOT=$(pwd)
 cd -
 
-. $CI_ROOT/script/static-checks/common.sh
+git fetch --unshallow --update-shallow origin
+git fetch --unshallow --update-shallow origin ${GERRIT_BRANCH} ${GERRIT_REFSPEC}
 
-merge_base=$(get_merge_base)
-if [[ -z "$merge_base" ]]; then
-    echo "Failed to find merge base, fetching entire change history"
-
-    # Set GERRIT_REFSPEC if not already defined
-    if [[ -z "$GERRIT_REFSPEC" ]]; then
-        if [[ "$TF_GERRIT_PROJECT" == *tf-a-tests ]]; then
-            GERRIT_REFSPEC="$TFTF_GERRIT_REFSPEC"
-        else
-            GERRIT_REFSPEC="$TF_GERRIT_REFSPEC"
-        fi
-    fi
-
-    git fetch --unshallow
-    git fetch origin "$GERRIT_REFSPEC"
-    git checkout FETCH_HEAD
-
-    merge_base=$(get_merge_base)
-
-    if [[ -z "$merge_base" ]]; then
-        echo "Failed to determine merge base after fetching. Exiting." >&2
-        exit 1
-    fi
-fi
-
-export merge_base
+export merge_base=$(git merge-base \
+    $(head -n1 .git/FETCH_HEAD | cut -f1) \
+    $(tail -n1 .git/FETCH_HEAD | cut -f1))
 
 export LOG_TEST_FILENAME=$(pwd)/static-checks.log