diff --git a/build b/build
index 0d5eceaf..0dc5aed2 100755
--- a/build
+++ b/build
@@ -7,16 +7,6 @@ TARGET="${1:-default}"
 # See https://nixos.wiki/wiki/FAQ/How_can_I_install_a_proprietary_or_unfree_package%3F
 export NIXPKGS_ALLOW_UNFREE=1
 
-function ensure_branch {
-  CURRENT_BRANCH=$(git rev-parse --abbrev-ref HEAD)
-  if [ "$CURRENT_BRANCH" != "$1" ]; then
-    echo
-    echo "You should be on branch '$1', but you are currently on branch '$CURRENT_BRANCH'."
-    echo "Aborting."
-    exit 1
-  fi
-}
-
 if [ "$TARGET" == "vm" ]; then
 
   (set -x; nix-build \
@@ -42,7 +32,8 @@ You can switch virtual consoles in the guest via QEMU monitor (ctrl-alt-2), send
 
 elif [ "$TARGET" == "develop" ]; then
 
-  ensure_branch "develop"
+  scripts/info-branch-commit
+  scripts/confirm-or-abort
 
   (set -x; nix-build \
     --arg updateCert ./pki/develop/cert.pem \
@@ -56,7 +47,8 @@ elif [ "$TARGET" == "develop" ]; then
 
 elif [ "$TARGET" == "validation" ]; then
 
-  ensure_branch "validation"
+  scripts/info-branch-commit
+  scripts/confirm-or-abort
 
   (set -x; nix-build \
     --arg updateCert ./pki/validation/cert.pem \
@@ -70,7 +62,8 @@ elif [ "$TARGET" == "validation" ]; then
 
 elif [ "$TARGET" == "master" ]; then
 
-  ensure_branch "master"
+  scripts/info-branch-commit
+  scripts/confirm-or-abort
 
   (set -x; nix-build \
     --arg updateCert ./pki/master/cert.pem \
@@ -82,12 +75,18 @@ elif [ "$TARGET" == "master" ]; then
   echo
   echo "Run ./result/bin/deploy-update to deploy."
 
-# Create a stuck system that will not self-update
-# usage: ./build stuck https://url-for-kiosk
 elif [ "$TARGET" == "stuck" ]; then
 
+  echo "Creating a stuck system that will not self-update."
+  echo
+
+  printf "Kiosk URL? "
+  read KIOSK_URL
+
+  KIOSK_URL=$(echo "$KIOSK_URL" | xargs) # Trim
+
   (set -x; nix-build \
-    --arg kioskUrl "$2" \
+    --arg kioskUrl "$KIOSK_URL" \
     --arg buildBundle false \
     --arg buildDisk false)
 
diff --git a/scripts/confirm-or-abort b/scripts/confirm-or-abort
new file mode 100755
index 00000000..e77fe512
--- /dev/null
+++ b/scripts/confirm-or-abort
@@ -0,0 +1,15 @@
+#!/usr/bin/env bash
+set -euo pipefail
+cd $(dirname "$0")
+
+if [ -n "${1:-}" ]; then
+
+  QUESTION="$1"
+
+else
+
+  QUESTION="Confirm?"
+
+fi
+
+./yes-no-question "$QUESTION" || (echo "Aborting." && exit 1)
diff --git a/scripts/info-branch-commit b/scripts/info-branch-commit
new file mode 100755
index 00000000..d576c34c
--- /dev/null
+++ b/scripts/info-branch-commit
@@ -0,0 +1,11 @@
+#! /usr/bin/env bash
+set -euo pipefail
+
+echo "On branch:"
+echo
+echo "    $(git rev-parse --abbrev-ref HEAD)"
+echo
+echo "With last commit:"
+echo
+echo "    $(git log -1 --pretty="%h %s")"
+echo
diff --git a/scripts/yes-no-question b/scripts/yes-no-question
new file mode 100755
index 00000000..4eaeeaed
--- /dev/null
+++ b/scripts/yes-no-question
@@ -0,0 +1,21 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+QUESTION="$1"
+
+while true; do
+
+  printf "$QUESTION [y/n] "
+  read ANSWER
+
+  if [ "$ANSWER" == "y" ]; then
+
+    exit 0
+
+  elif [ "$ANSWER" == "n" ]; then
+
+    exit 1
+
+  fi
+
+done