It's probably a good idea to have the latest firmware on a REDmag, just in case you're in the middle of nowhere and things go awry. So why not have a dedicate REDmag for just this purpose. Sure you could use a 64GB mag, but at $950 a pop that's a tad pricey.
So is there anyway there could be a cheap 1GB SSD for just this purpose? Maybe there's already a better solution than this.
Just a thought.