I have a device that has LEDE on it. I want to change its firmware, but before that, I want to keep the original firmware. Is it possible to creat an image from the current firmware and then install the new one? I want to be able to install the original one if I need.
cat /proc/mtd cat /dev/mtd0 > /tmp/mtd0.bin ...
There is no easy solution for this, especially not a generic one (e.g. the approach above would be fatal for any device using NAND as flash and, unless taken carefully and with a deeper understanding which partition covers what, is dangerous for all devices) - and it's generally not a supported approach.
Which brand and model?