Thoughts on feasibility of self-updating from an SD card

[dlchambers]

I'd like to make my Teensy be able to update it's program from a HEX file on an SPI-connected SD card.

I'm using a Teensy 3.2 with an I2C wifi module and SPI SD card.

I'd like to be able to have the Teensy download an update (hex file) and store it on the SD card, then have the Teensy replace it's firmware with that image (hex) file on the SD.
The wifi part isn't really germane to the updating, just some background as to how the update is obtained.

So the question is really about the feasibility of having a Teensy reprogram itself off an SPI-connected SD card.

Has anyone done anything like this?
Any thoughts, ideas, examples would be GREATLY appreciated.

-Dave

 

[GremlinWrangler]

Short answer is that the Teensy 3.x was carefully crafted to be unbrickable, and doing this requires removing some of the safety nets that avoid that so proceed with caution, especially if this is a commercial project.

There are a couple of projects around the forum looking at OTA updates. As far as I know all currently have 'handle with care' caveats attached in terms of using them anywhere you can't get a USB cable in to unbrick things. A off the shelf solution seems to be http://www.utasker.com/kinetis/TEENSY_3.1.html though have not personally used it.

Google dug this one up from the forums, unsure if there are more recent or more complete projects
https://forum.pjrc.com/threads/29607-Over-the-air-updates