update

Author: ThomasFarstrike

docs/apps/bundling-apps.md

@@ -1,11 +1,18 @@
 # Bundling Apps
 
-To bundle your app in an .mpk file, just make an uncompressed .zip file of it, without including the top-level `com.micropythonos.helloworld/` folder.
+To bundle your app in an .mpk file, just make an uncompressed "zip" file of it, without including the top-level `com.micropythonos.helloworld/` folder.
+
+It's recommended to make the .mpk file deterministic by:
+- setting the file timestamps to a fixed value
+- sorting the files, so the order is fixed
+- excluding extra file attributes and directories
 
 For example:
 
 ```
 cd com.micropythonos.helloworld/
-zip -r0 /tmp/com.micropythonos.helloworld_0.0.2.mpk .
+find . -type f -exec touch -t 202501010000.00 {} \; # set fixed timestamp
+find . -type f | sort | TZ=CET zip -X -r -0 /tmp/com.micropythonos.helloworld_0.0.2.mpk -@ # sort, -Xclude extra attributes, -recurse into directories and -0 compression
 ```
 
+Take a look at [`scripts/bundleapps.sh`](https://github.com/MicroPythonOS/MicroPythonOS/blob/main/scripts/bundleapps.sh) to see how the MicroPythonOS default apps are bundled.