I currently have a working Raspbian installation on my Raspberry Pi that I use to read my car's diagnostic info using OBD2 (by setting up a Wifi hotspot on boot and opening a socket relaying data to an OBD serial interface)

However, I can't properly shut down the Pi, because it runs off the car's 12V. So in order to prevent filesystem corruption I would like to make the OS read-only.

I didn't find anything useful on Google unfortunately. I'd like to have something working like a live CD (squashFS image). Can I just make a squashFS image of my current root partition?

What about log files and such? Do I need to have some kind of RAM filesystem for the system temp files or something?

  • You might consider exploring Pi TinyCore Linux which is read only by default, and more appropriate for what you want.
    – avra
    Nov 28, 2013 at 10:44

2 Answers 2


I run Arch Linux on Pi, I had to change a few things to get it to run fine with the file system mounted as ro.

I followed this blog to setup everything, check it out.

I understand that arch and debian and quite different in startup scripts but it might be a starting point.


have you thought about adding a sense wire to the Acc of the car and a script watching it on a GPIO pin to detect when it's shutting off and run "sudo shutdown -h now" with a diode & capacitor after the sensor to supply just enough power to give it adequate time to power down safely before its drained.

  • Thank you but it seems a bit much as I really don't need a read/write system for my application. Dec 10, 2013 at 13:23

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