Run HEX program from SD with another program I want to write a program in which I can select a HEX file recorded on a SD card (via a LED screen, etc.) and run it, i.e. transfer control to it, like launching programs on a PC. Is this possible and if so, how? I only found ways to directly run a sketch from an SD card without that &quot;program&quot;
Not with an Uno, no, it's not possible. Or it's very very hard and the results would be less than desirable. You need a proper MCU with lots of RAM and the ability to run code from it, which you can't with an Uno.
It would be less work to write your own scripting language to control things from a text file.