I have an Arduino Yún, and it only has 16mb flash onboard for the Linux. I was wondering of it is possible to put a bootloader on the flash that uses the sd card as a rootfs? i want to be able to do more projects on it than those that can fit in 16 MB flash.
And the Arduino team finally figured it out:
I am using Yun as well for my projects. I don't boot from SD card, but I store a lot of Python code there and it works for me. I've also seen this article that might be interesting for you. I haven't tried to do it on my Yun but I think it should work... This is example how to install node.js on the Yun (SD card), so in theory you could use the same approach for all additional software you want to run.