diff --git a/handwritten/spanner/.kokoro/trampoline_v2.sh b/handwritten/spanner/.kokoro/trampoline_v2.sh
index 2ed993bbdff3..46d7c10a51dc 100755
--- a/handwritten/spanner/.kokoro/trampoline_v2.sh
+++ b/handwritten/spanner/.kokoro/trampoline_v2.sh
@@ -254,9 +254,6 @@ else
     PROJECT_ROOT="$(repo_root $(pwd))/handwritten/spanner"
 fi
 
-log_yellow "Changing to the project root: ${PROJECT_ROOT}."
-cd "${PROJECT_ROOT}"
-
 # Auto-injected conditional check
 # Check if the package directory has changes. If not, skip tests.
 if [[ "${RUNNING_IN_CI:-}" == "true" ]]; then
@@ -269,6 +266,7 @@ if [[ "${RUNNING_IN_CI:-}" == "true" ]]; then
     # Safe default: HEAD~1..HEAD
     DIFF_RANGE="HEAD~1..HEAD"
 
+    git fetch --deepen=10 2>/dev/null || true
     if git diff --quiet "${DIFF_RANGE}" -- "${RELATIVE_PKG_PATH}"; then
         echo "No changes detected in ${RELATIVE_PKG_PATH}. Skipping tests."
         exit 0
@@ -277,6 +275,9 @@ if [[ "${RUNNING_IN_CI:-}" == "true" ]]; then
     fi
 fi
 
+log_yellow "Changing to the project root: ${PROJECT_ROOT}."
+cd "${PROJECT_ROOT}"
+
 # To support relative path for `TRAMPOLINE_SERVICE_ACCOUNT`, we need
 # to use this environment variable in `PROJECT_ROOT`.
 if [[ -n "${TRAMPOLINE_SERVICE_ACCOUNT:-}" ]]; then
@@ -316,6 +317,7 @@ done
 # We want to support legacy style TRAMPOLINE_BUILD_FILE used with V1
 # script: e.g. "github/repo-name/.kokoro/run_tests.sh"
 TRAMPOLINE_BUILD_FILE="${TRAMPOLINE_BUILD_FILE#github/*/}"
+TRAMPOLINE_BUILD_FILE="${TRAMPOLINE_BUILD_FILE#handwritten/spanner/}"
 log_yellow "Using TRAMPOLINE_BUILD_FILE: ${TRAMPOLINE_BUILD_FILE}"
 
 # ignore error on docker operations and test execution
diff --git a/handwritten/spanner/.trampolinerc b/handwritten/spanner/.trampolinerc
index dea7e9541e63..5fc2253137db 100644
--- a/handwritten/spanner/.trampolinerc
+++ b/handwritten/spanner/.trampolinerc
@@ -49,4 +49,4 @@ if [[ -z "${TRAMPOLINE_BUILD_FILE:-}" ]]; then
 fi
 
 # Secret Manager secrets.
-source ${PROJECT_ROOT}/handwritten/spanner/.kokoro/populate-secrets.sh
+source ${PROJECT_ROOT}/.kokoro/populate-secrets.sh
diff --git a/handwritten/spanner/system-test/spanner.ts b/handwritten/spanner/system-test/spanner.ts
index 5ee4fcbd706b..56cc895018db 100644
--- a/handwritten/spanner/system-test/spanner.ts
+++ b/handwritten/spanner/system-test/spanner.ts
@@ -1193,7 +1193,11 @@ describe('Spanner', () => {
           assert.fail('Expected an error to be thrown, but it was not.');
         } catch (err: any) {
           KOKORO_JOB_NAME?.includes('system-test-regular-session')
-            ? assert.strictEqual(err.code, grpc.status.FAILED_PRECONDITION)
+            ? assert.ok(
+                err.code === grpc.status.FAILED_PRECONDITION ||
+                  err.code === grpc.status.OUT_OF_RANGE,
+                `Expected FAILED_PRECONDITION (9) or OUT_OF_RANGE (11), got ${err.code}`
+              )
             : assert.strictEqual(err.code, grpc.status.INVALID_ARGUMENT);
         }
       };