A country that I know...
They can arrange the installation of a brand new box onto the military aircraft in a month flat. But if anyone ever needed to update the software on that box, it might take years. YEARS!
It would be better, faster, cheaper to remove the original box from the airplane, take it out behind the wood shed (and then load the new software, change the PN decal, and paint it a different colour to confuse them), and then reinstall the "brand new" box (move along, nothing to see here) back into the same spot on the airplane. Might take five weeks.
Because software is such an impediment, it would actually be better to design military avionics relying on miniaturized mechanisms (gears, levers, Johnson rods) to perform and control all the complicated functions. Just to avoid The Nightmare That Is Software.
Biting the hand that feeds IT
