diff --git a/bin/omarchy-iso-installer b/bin/omarchy-iso-installer
index 4605a00..12a6488 100755
--- a/bin/omarchy-iso-installer
+++ b/bin/omarchy-iso-installer
@@ -2,53 +2,50 @@
 # Preview the shipped Omarchy installer dashboard without building an ISO.
 set -euo pipefail
 
+write_simulation_state() {
+  local state_file="$1" started_at="$2" phase_started_at="$3" current_phase="$4"
+  local finished_at="${5:-null}" temporary="${state_file}.tmp"
+
+  jq -n \
+    --argjson started_at "$started_at" \
+    --argjson phase_started_at "$phase_started_at" \
+    --arg current_phase "$current_phase" \
+    --argjson finished_at "$finished_at" \
+    '{
+      started_at: $started_at,
+      phase_started_at: $phase_started_at,
+      current_phase: $current_phase
+    } + if $finished_at == null then {} else {finished_at: $finished_at} end' \
+    >"$temporary"
+  mv -f -- "$temporary" "$state_file"
+}
+
 simulate_install() {
   local state_file="$1"
+  local started_at="$EPOCHREALTIME"
+  local phase phase_started_at finished_at duration i
+  local -a phases=(
+    "Starting installation" 0.5
+    "Preparing live environment" 0.8
+    "Installing Arch + Omarchy" 5.0
+    "Configuring system" 1.2
+    "Finalizing Limine boot" 1.0
+    "Finalizing user" 1.0
+    "Configuring login" 0.6
+    "Validating boot setup" 0.8
+  )
 
-  python - "$state_file" <<'PY'
-import json
-import os
-import sys
-import time
+  for ((i = 0; i < ${#phases[@]}; i += 2)); do
+    phase="${phases[i]}"
+    duration="${phases[i + 1]}"
+    phase_started_at="$EPOCHREALTIME"
+    write_simulation_state "$state_file" "$started_at" "$phase_started_at" "$phase"
+    sleep "$duration"
+  done
 
-state_file = sys.argv[1]
-started_at = time.time()
-phases = [
-    ("Starting installation", 0.5),
-    ("Preparing live environment", 0.8),
-    ("Installing Arch + Omarchy", 5.0),
-    ("Configuring system", 1.2),
-    ("Finalizing Limine boot", 1.0),
-    ("Finalizing user", 1.0),
-    ("Configuring login", 0.6),
-    ("Validating boot setup", 0.8),
-]
-
-
-def write_state(current_phase, phase_started_at, finished_at=None):
-    state = {
-        "started_at": started_at,
-        "phase_started_at": phase_started_at,
-        "current_phase": current_phase,
-    }
-    if finished_at is not None:
-        state["finished_at"] = finished_at
-
-    temporary = f"{state_file}.tmp"
-    with open(temporary, "w") as output:
-        json.dump(state, output)
-    os.replace(temporary, state_file)
-
-
-for phase, duration in phases:
-    phase_started_at = time.time()
-    write_state(phase, phase_started_at)
-    time.sleep(duration)
-
-finished_at = time.time()
-write_state("Installation complete", finished_at, finished_at)
-time.sleep(0.3)
-PY
+  finished_at="$EPOCHREALTIME"
+  write_simulation_state "$state_file" "$started_at" "$finished_at" "Installation complete" "$finished_at"
+  sleep 0.3
 }
 
 if [[ ${1:-} == "--simulate-install" ]]; then