diff --git a/build.sh b/build.sh
index 226f864..374aa36 100755
--- a/build.sh
+++ b/build.sh
@@ -39,7 +39,8 @@ pathlib.Path("dist/pico-main.py").write_text(pathlib.Path("pico/main.py").read_t
 print("copied pico-main.py")
 import zipfile  # PM_K-1 CircuitPython drive bundle (download → unzip onto CIRCUITPY)
 with zipfile.ZipFile("dist/pm_k1_circuitpy.zip", "w", zipfile.ZIP_DEFLATED) as z:
-    for f in ("code.py", "boot.py", "programs.json", "font_s.bin", "font_m.bin", "font_l.bin", "README.md"):
+    for f in ("code.py", "boot.py", "programs.json", "font_s.bin", "font_m.bin", "font_l.bin",
+              "README.md", "protect-firmware.sh"):
         z.write("pico-cp/" + f, f)
     z.write("dist/editor.html", "editor.html")        # offline copy of the editor, on the drive
 print("zipped pm_k1_circuitpy.zip")
diff --git a/pico-cp/README.md b/pico-cp/README.md
index 72da209..81047b5 100644
--- a/pico-cp/README.md
+++ b/pico-cp/README.md
@@ -36,6 +36,21 @@ If the editor says **no MIDI input is connected**, copy **`boot.py`** onto `CIRC
 **power-cycle** the Pico (`boot.py` only runs on a full reset). It frees a USB endpoint (drops the
 unused HID interface) so the MIDI port is guaranteed to appear alongside the drive.
 
+## Protect the firmware (so end users only see the editor + their tracks)
+
+To stop someone accidentally deleting the firmware, **hide it** — the files keep running and
+"Save to device" still works, but only `editor.html` + `programs.json` show in the file browser.
+On the host, with the drive mounted, run the included helper (needs `fatattr`):
+
+```
+./protect-firmware.sh /media/$USER/CIRCUITPY      # hides code.py, boot.py, font_*.bin, README, itself
+```
+
+(Reveal again with `fatattr -h <file>`.) For a **hard lock** — nothing on the drive can be changed
+from the computer at all — put `storage.remount("/", readonly=True)` in `boot.py`; but then the
+editor's *Save to device* can't write either, so you'd reprogram by temporarily removing that line
+(or gating it behind a held button at power-on). Hiding is usually the right balance.
+
 ## Controls (same as the MicroPython build)
 
 - **Touch:** on‑screen `◀◀ / ▶ / ▶▶` (prev · play/stop · next) and `− / TAP / +`.
diff --git a/pico-cp/protect-firmware.sh b/pico-cp/protect-firmware.sh
new file mode 100755
index 0000000..a5608ab
--- /dev/null
+++ b/pico-cp/protect-firmware.sh
@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Hide the PM_K-1 firmware files on a CIRCUITPY drive so an end user only sees
+# editor.html + programs.json — the two files they're meant to touch. The hidden
+# files keep running, and the editor's "Save to device" still works (programs.json
+# stays writable). This just prevents *accidental* deletion of the firmware.
+#
+# Run it on the HOST, pointing at the mounted drive:
+#     ./protect-firmware.sh /media/$USER/CIRCUITPY
+# (defaults to the current directory if run from inside the drive). Needs `fatattr`
+# (sudo apt install fatattr) — or use the mtools fallback printed below.
+#
+# To reveal them again:  fatattr -h <file>
+set -euo pipefail
+DIR="${1:-.}"
+HIDE=(code.py boot.py font_s.bin font_m.bin font_l.bin README.md protect-firmware.sh boot_out.txt)
+
+if command -v fatattr >/dev/null 2>&1; then
+  for f in "${HIDE[@]}"; do
+    if [ -e "$DIR/$f" ]; then fatattr +h "$DIR/$f" && echo "hidden: $f"; fi
+  done
+  echo "Done — the drive now shows only editor.html + programs.json."
+else
+  echo "fatattr not found.  Install it:  sudo apt install fatattr   (or dnf/pacman equivalent)"
+  echo "Or, with mtools, run e.g.:  mattrib -i /dev/sdX1 +h ::code.py ::boot.py ::font_*.bin"
+  exit 1
+fi