Archived Forum

As an alternative to the IPE-R1, Raspbian can be configured to run in read-only mode for increased stability when running a "rock-solid gateway" (optional but recommended unless running from hdd). Following a discussion on another thread I decided to post this guide I had prepared for the emonhub documentation as it may help other users. 

(This avoids any of the updating and driver issues encountered by using the IPE-R1.)

Download the latest Raspbian Image  and load to SD-card

Start by updating the downloaded Raspbian image once it's booted

sudo apt-get update
sudo apt-get -y upgrade

Then run these commands to make changes to filesystem (sorry, not indented, so longer lines won't  wrap)

sudo cp /etc/default/rcS /etc/default/rcS.orig
sudo sh -c "echo 'RAMTMP=yes' >> /etc/default/rcS"
sudo mv /etc/fstab /etc/fstab.orig
sudo sh -c "echo 'tmpfs           /tmp            tmpfs   nodev,nosuid,size=30M,mode=1777       0    0' >> /etc/fstab"
sudo sh -c "echo 'tmpfs           /var/log        tmpfs   nodev,nosuid,size=30M,mode=1777       0    0' >> /etc/fstab"
sudo sh -c "echo 'proc            /proc           proc    defaults                              0    0' >> /etc/fstab"
sudo sh -c "echo '/dev/mmcblk0p1  /boot           vfat    defaults                              0    2' >> /etc/fstab"
sudo sh -c "echo '/dev/mmcblk0p2  /               ext4    defaults,ro,noatime,errors=remount-ro 0    1' >> /etc/fstab"
sudo sh -c "echo ' ' >> /etc/fstab"
sudo mv /etc/mtab /etc/mtab.orig
sudo ln -s /proc/self/mounts /etc/mtab

The Pi will now run in Read-Only mode from the next restart.

Before restarting create two shortcut commands to switch between read-only and write access modes.

Firstly “ rpi-rw “ will be the command to unlock the filesystem for editing, run

sudo nano /usr/bin/rpi-rw

and add the following​ to the blank file that opens

#!/bin/sh
sudo mount -o remount,rw /dev/mmcblk0p2  /
echo "Filesystem is unlocked - Write access"
echo "type ' rpi-ro ' to lock"

save and exit using ' ctrl-x -> y -> enter ' and then to make this executable run

sudo chmod +x  /usr/bin/rpi-rw

Next “ rpi-ro “ will be the command to lock the filesytem down again, run

sudo nano /usr/bin/rpi-ro

and add the following to the blank file that opens

#!/bin/sh
sudo mount -o remount,ro /dev/mmcblk0p2  /
echo "Filesystem is locked - Read Only access"
echo "type ' rpi-rw ' to unlock"

save and exit using ' ctrl-x -> y -> enter ' and then to make this executable run

sudo chmod +x  /usr/bin/rpi-ro

Lastly reboot for changes to take effect (note - if  serial UART  access required make those changes before restarting)

sudo shutdown -r now

Remember to use “ rpi-rw “ before making any changes and then to use “ rpi-ro “ afterwards to lock the filesystem down again.

Further info on configuring Raspbian as read-only can be found on debian site and rpi forum

Paul