diff --git a/migrations/1788256455.sh b/migrations/1788256455.sh
index 6c7463ec..e133604e 100644
--- a/migrations/1788256455.sh
+++ b/migrations/1788256455.sh
@@ -10,43 +10,70 @@ polkit=/etc/pam.d/polkit-1
 # failures never counted toward the shared tally. The setup commands now defer to
 # system-auth; this repairs the files the old ones already wrote.
 #
-# In scope only when the file exists, no package owns it (Omarchy wrote it), it
-# does not already defer to system-auth, and it carries an Omarchy hardware-auth
-# marker (the clamshell gate, pam_fprintd, or the FIDO2 authfile). That pins the
-# repair to the exact stack the setup commands produced and leaves an
-# administrator's own polkit-1 untouched. Idempotent by construction: once
-# system-auth is included, this run and every other user's run no-op.
-if [[ -f $polkit ]] &&
-  ! pacman -Qo "$polkit" &>/dev/null &&
-  ! grep -qE '^auth[[:space:]]+include[[:space:]]+system-auth' "$polkit" &&
-  grep -qE 'omarchy-hw-laptop-closed|pam_fprintd\.so|authfile=/etc/fido2/fido2' "$polkit"; then
+# Only the exact stack those commands produced is touched. Every non-blank,
+# non-comment line must be one of the known hardware-auth auth lines (the
+# clamshell gate, pam_fprintd, or the FIDO2 pam_u2f line) or a bare
+# `X required pam_unix.so`; all four bare pam_unix lines must be present; and
+# system-auth must not already be included. This matches the fingerprint, FIDO2,
+# combined, and post-removal (markerless, both remove commands strip only their
+# own marker lines) layouts, and refuses any administrator-authored stack that
+# carries other directives. The repair replaces only the bare pam_unix lines, so
+# comments and the hardware-auth lines are preserved verbatim.
 
+is_omarchy_vulnerable_stack() {
+  local file=$1 line
+  local re_gate='^auth[[:space:]]+\[success=1 default=ignore\][[:space:]]+pam_exec\.so quiet /usr/bin/omarchy-hw-laptop-closed[[:space:]]*$'
+  local re_fprintd='^auth[[:space:]]+sufficient[[:space:]]+pam_fprintd\.so[[:space:]]*$'
+  local re_u2f='^auth[[:space:]]+sufficient[[:space:]]+pam_u2f\.so cue authfile=/etc/fido2/fido2[[:space:]]*$'
+  local re_bare='^(auth|account|password|session)[[:space:]]+required[[:space:]]+pam_unix\.so[[:space:]]*$'
+  local phase
+
+  # Already fixed, or partially converted: leave it alone (also makes reruns no-op).
+  if grep -qE '(auth|account|password|session)[[:space:]]+include[[:space:]]+system-auth' "$file"; then
+    return 1
+  fi
+
+  # The vulnerable signature: all four phases delegated to a bare pam_unix.
+  for phase in auth account password session; do
+    grep -qE "^${phase}[[:space:]]+required[[:space:]]+pam_unix\.so[[:space:]]*\$" "$file" || return 1
+  done
+
+  # Every meaningful line must be one Omarchy itself wrote; anything else means
+  # an administrator has edited this file, so it is not ours to rewrite.
+  while IFS= read -r line || [[ -n $line ]]; do
+    [[ -z ${line//[[:space:]]/} ]] && continue
+    [[ $line == \#* ]] && continue
+    [[ $line =~ $re_gate || $line =~ $re_fprintd || $line =~ $re_u2f || $line =~ $re_bare ]] && continue
+    return 1
+  done <"$file"
+
+  return 0
+}
+
+if [[ -f $polkit ]] && is_omarchy_vulnerable_stack "$polkit"; then
   echo "Rewriting $polkit to defer to system-auth (restores pam_faillock lockout)..."
 
-  # Keep the configured hardware-auth auth lines verbatim (the clamshell gate and
-  # the pam_fprintd / pam_u2f 'sufficient' lines); only the bare pam_unix stack is
-  # replaced with the system-auth includes the vendor file and the sudo stack use.
-  hw_auth=$(grep -E '^auth' "$polkit" | grep -vE 'pam_unix\.so')
-
-  rebuilt=$(
-    [[ -n $hw_auth ]] && printf '%s\n' "$hw_auth"
-    printf 'auth      include system-auth\n'
-    printf 'account   include system-auth\n'
-    printf 'password  include system-auth\n'
-    printf 'session   include system-auth\n'
-  )
-
   backup="$polkit.omarchy-bak.$(date +%s)"
-  if sudo cp -a "$polkit" "$backup"; then
-    printf '%s\n' "$rebuilt" | sudo tee "$polkit" >/dev/null
+  if ! sudo cp -a "$polkit" "$backup"; then
+    echo "Could not back up $polkit; leaving it unchanged so the migration retries." >&2
+    exit 1
+  fi
 
-    if grep -qE '^auth[[:space:]]+include[[:space:]]+system-auth' "$polkit"; then
-      echo "Restored polkit brute-force protection. Previous file saved at $backup."
-    else
-      echo "polkit repair could not be verified; restoring the original file." >&2
-      sudo cp -a "$backup" "$polkit"
-    fi
+  # Replace only the bare pam_unix lines; keep comments, blank lines, and the
+  # hardware-auth (gate / pam_fprintd / pam_u2f) lines exactly as they are.
+  rebuilt=$(sed -E 's/^(auth|account|password|session)([[:space:]]+)required[[:space:]]+pam_unix\.so[[:space:]]*$/\1\2include system-auth/' "$polkit")
+
+  if ! printf '%s\n' "$rebuilt" | sudo tee "$polkit" >/dev/null; then
+    echo "Could not write $polkit; restoring the original." >&2
+    sudo cp -a "$backup" "$polkit" || true
+    exit 1
+  fi
+
+  if grep -qE '^auth[[:space:]]+include[[:space:]]+system-auth' "$polkit"; then
+    echo "Restored polkit brute-force protection. Previous file saved at $backup."
   else
-    echo "Administrator privileges are required to repair $polkit. Run omarchy-migrate again from a terminal." >&2
+    echo "polkit repair could not be verified; restoring the original file." >&2
+    sudo cp -a "$backup" "$polkit"
+    exit 1
   fi
 fi
diff --git a/test/shell.d/security-polkit-migration-test.sh b/test/shell.d/security-polkit-migration-test.sh
new file mode 100644
index 00000000..b00e4681
--- /dev/null
+++ b/test/shell.d/security-polkit-migration-test.sh
@@ -0,0 +1,173 @@
+#!/bin/bash
+
+set -euo pipefail
+
+source "$(dirname "$0")/base-test.sh"
+
+# Exercises migrations/1788256455.sh, which repairs an Omarchy-created
+# /etc/pam.d/polkit-1 that lists pam_unix directly (dropping pam_faillock)
+# instead of including system-auth. The migration keeps its production path
+# fixed; as in sshd-hardening-migration-test.sh, this test rewrites that one
+# assignment in the input fed to bash and stubs sudo so nothing touches the
+# host's /etc.
+
+test_dir=$(mktemp -d)
+trap 'rm -rf "$test_dir"' EXIT
+
+migration="$ROOT/migrations/1788256455.sh"
+stub_bin="$test_dir/bin"
+mkdir -p "$stub_bin"
+
+# sudo stub: log, optionally refuse (SUDO_ALLOWED=0), and optionally make a
+# `tee` write vanish (WRITE_BREAKS=1) so the verification/restore path is
+# exercised. Otherwise run the real command so cp/tee act on the temp file.
+cat >"$stub_bin/sudo" <<'STUB'
+#!/bin/bash
+printf 'sudo %s\n' "$*" >>"${CALL_LOG:?}"
+if [[ ${SUDO_ALLOWED:-1} != 1 ]]; then
+  exit 1
+fi
+if [[ ${WRITE_BREAKS:-0} == 1 && $1 == tee ]]; then
+  cat >/dev/null
+  exit 0
+fi
+exec "$@"
+STUB
+chmod +x "$stub_bin"/*
+
+# Run the migration against a polkit-1 file seeded with $1; leaves the result in
+# "$test_dir/<scenario>/polkit-1" and records the exit status in migrate_rc.
+migrate_rc=0
+run_migration() {
+  local scenario=$1 content=$2
+  local dir="$test_dir/$scenario"
+  local polkit="$dir/polkit-1"
+  mkdir -p "$dir"
+  printf '%s' "$content" >"$polkit"
+  : >"$test_dir/$scenario.calls"
+
+  migrate_rc=0
+  sed "s|^polkit=/etc/pam.d/polkit-1\$|polkit=$polkit|" "$migration" |
+    CALL_LOG="$test_dir/$scenario.calls" PATH="$stub_bin:$PATH" \
+      SUDO_ALLOWED="${SUDO_ALLOWED:-1}" WRITE_BREAKS="${WRITE_BREAKS:-0}" \
+      bash -euo pipefail >/dev/null 2>&1 || migrate_rc=$?
+}
+
+result() { cat "$test_dir/$1/polkit-1"; }
+
+# The four layouts the old setup / remove commands leave behind.
+fingerprint_stack='auth      [success=1 default=ignore] pam_exec.so quiet /usr/bin/omarchy-hw-laptop-closed
+auth      sufficient pam_fprintd.so
+auth      required pam_unix.so
+
+account   required pam_unix.so
+password  required pam_unix.so
+session   required pam_unix.so
+'
+fido2_stack='auth      sufficient pam_u2f.so cue authfile=/etc/fido2/fido2
+auth      required pam_unix.so
+
+account   required pam_unix.so
+password  required pam_unix.so
+session   required pam_unix.so
+'
+both_stack='auth      [success=1 default=ignore] pam_exec.so quiet /usr/bin/omarchy-hw-laptop-closed
+auth      sufficient pam_fprintd.so
+auth      sufficient pam_u2f.so cue authfile=/etc/fido2/fido2
+auth      required pam_unix.so
+
+account   required pam_unix.so
+password  required pam_unix.so
+session   required pam_unix.so
+'
+# What both remove commands leave: their own marker lines stripped, the bare
+# pam_unix stack (and no marker) behind.
+markerless_stack='auth      required pam_unix.so
+
+account   required pam_unix.so
+password  required pam_unix.so
+session   required pam_unix.so
+'
+fixed_stack='auth      sufficient pam_fprintd.so
+auth      include system-auth
+account   include system-auth
+password  include system-auth
+session   include system-auth
+'
+# An administrator's own stack that happens to use pam_fprintd but carries an
+# extra directive Omarchy never writes.
+admin_stack='auth      sufficient pam_fprintd.so
+auth      required pam_unix.so
+auth      optional pam_permit.so
+account   required pam_unix.so
+password  required pam_unix.so
+session   required pam_unix.so
+'
+
+# Every phase of a repaired stack must defer to system-auth and no bare pam_unix
+# may remain in the account/password/session block.
+assert_repaired() {
+  local scenario=$1 phase
+  for phase in auth account password session; do
+    grep -qE "^${phase}[[:space:]]+include[[:space:]]+system-auth" <<<"$(result "$scenario")" ||
+      fail "$scenario: $phase defers to system-auth" "$(result "$scenario")"
+  done
+  ! grep -qE '^(account|password|session)[[:space:]]+required[[:space:]]+pam_unix' <<<"$(result "$scenario")" ||
+    fail "$scenario: no bare pam_unix remains" "$(result "$scenario")"
+}
+
+run_migration fingerprint "$fingerprint_stack"
+(( migrate_rc == 0 )) || fail "fingerprint stack migrates cleanly"
+assert_repaired fingerprint
+grep -qF 'pam_fprintd.so' <<<"$(result fingerprint)" || fail "fingerprint line is preserved"
+grep -qF 'omarchy-hw-laptop-closed' <<<"$(result fingerprint)" || fail "clamshell gate is preserved"
+pass "migration repairs the fingerprint stack and keeps its hardware-auth lines"
+
+run_migration fido2 "$fido2_stack"
+(( migrate_rc == 0 )) || fail "fido2 stack migrates cleanly"
+assert_repaired fido2
+grep -qF 'pam_u2f.so cue authfile=/etc/fido2/fido2' <<<"$(result fido2)" || fail "FIDO2 line is preserved"
+pass "migration repairs the FIDO2 stack and keeps its hardware-auth line"
+
+run_migration both "$both_stack"
+(( migrate_rc == 0 )) || fail "combined stack migrates cleanly"
+assert_repaired both
+grep -qF 'pam_fprintd.so' <<<"$(result both)" && grep -qF 'pam_u2f.so' <<<"$(result both)" ||
+  fail "both hardware-auth lines are preserved"
+pass "migration repairs a combined fingerprint+FIDO2 stack"
+
+run_migration markerless "$markerless_stack"
+(( migrate_rc == 0 )) || fail "markerless stack migrates cleanly"
+assert_repaired markerless
+pass "migration repairs the markerless post-removal stack"
+
+run_migration comment "# managed by omarchy
+$fingerprint_stack"
+(( migrate_rc == 0 )) || fail "commented stack migrates cleanly"
+assert_repaired comment
+grep -qxF '# managed by omarchy' <<<"$(result comment)" || fail "comments are preserved through the rewrite"
+pass "migration repairs a commented stack and preserves the comment"
+
+run_migration fixed "$fixed_stack"
+[[ "$(result fixed)" == "$(printf '%s' "$fixed_stack")" ]] || fail "an already-fixed stack is left byte-for-byte unchanged"
+! grep -q '^sudo ' "$test_dir/fixed.calls" || fail "an already-fixed stack triggers no privileged writes"
+pass "migration is idempotent: an already-fixed stack is untouched"
+
+run_migration admin "$admin_stack"
+[[ "$(result admin)" == "$(printf '%s' "$admin_stack")" ]] || fail "an administrator-authored stack is left unchanged"
+! grep -q '^sudo ' "$test_dir/admin.calls" || fail "an administrator-authored stack triggers no privileged writes"
+pass "migration refuses a stack carrying non-Omarchy directives"
+
+# Privilege failure is the retryable case: the migration must exit non-zero so
+# omarchy-migrate does not record it complete, and must leave the file unchanged.
+SUDO_ALLOWED=0 run_migration no-sudo "$fingerprint_stack"
+(( migrate_rc != 0 )) || fail "the migration stays pending when privileges are unavailable"
+[[ "$(result no-sudo)" == "$(printf '%s' "$fingerprint_stack")" ]] || fail "a failed repair leaves the original file intact"
+pass "migration exits non-zero and preserves the file when sudo is refused"
+
+# A write that does not take effect must be caught by verification, restored,
+# and reported as a failure rather than silently marked complete.
+WRITE_BREAKS=1 run_migration verify-fail "$fingerprint_stack"
+(( migrate_rc != 0 )) || fail "a failed verification exits non-zero"
+[[ "$(result verify-fail)" == "$(printf '%s' "$fingerprint_stack")" ]] || fail "a failed verification restores the original file"
+pass "migration exits non-zero and restores when the write cannot be verified"