diff --git a/components/nimbus/ios/scripts/bootstrap.sh b/components/nimbus/ios/scripts/bootstrap.sh
index 3f37f12172..379454a0d4 100755
--- a/components/nimbus/ios/scripts/bootstrap.sh
+++ b/components/nimbus/ios/scripts/bootstrap.sh
@@ -16,6 +16,8 @@
 #
 # In addition, the `nimbus-fml.sh` and `nimbus-fml-configuration.local.sh` are added to `./gitignore`.
 #
+set -euo pipefail
+
 CMDNAME=$(basename "$0")
 AS_BASE="https://raw.githubusercontent.com/mozilla/application-services/main"
 PATH_PREFIX="components/nimbus/ios/scripts"
@@ -61,7 +63,6 @@ fail_trap() {
 
 #Stop execution on any error
 trap 'fail_trap $? $LINENO' ERR
-set -e
 
 # Process the command line args.
 while (( "$#" )); do
diff --git a/components/nimbus/ios/scripts/nimbus-fml-configuration.sh b/components/nimbus/ios/scripts/nimbus-fml-configuration.sh
index 042d9e273d..320c9f5073 100755
--- a/components/nimbus/ios/scripts/nimbus-fml-configuration.sh
+++ b/components/nimbus/ios/scripts/nimbus-fml-configuration.sh
@@ -4,6 +4,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+set -euo pipefail
+
 # Local modifications/additions can be made in `nimbus-fml-configuration.local.sh`
 
 ## Set the channel that is used to generate the Swift code.
diff --git a/components/nimbus/ios/scripts/nimbus-fml.sh b/components/nimbus/ios/scripts/nimbus-fml.sh
index a4f090c33d..f1d817a610 100755
--- a/components/nimbus/ios/scripts/nimbus-fml.sh
+++ b/components/nimbus/ios/scripts/nimbus-fml.sh
@@ -20,6 +20,7 @@
 # 7. Add the "FML.swift" file in the `Generated` folder to your project.
 # 8. Add the same "FML.swift" from the `Generated` folder as Output Files of the newly created "Run Script" step.
 # 9. Start using the generated feature code.
+set -euo pipefail
 
 DIRNAME=$(dirname "$0")
 
@@ -112,6 +113,9 @@ find_as_version() {
     AS_VERSION=${number_string//\.0\./\.} # rust-component-swift tags have a middle `.0.` to force it to align with spm. We remove it
 }
 FRESHEN_FML=
+AS_VERSION=
+MOZ_APPSERVICES_LOCAL=
+REPO_FILES=
 NIMBUS_DIR="$SOURCE_ROOT/build/nimbus"
 
 export CACHE_DIR="$NIMBUS_DIR/fml-cache"