Is it possible to flash an arduino through another arduino without using a computer?

Question

Arduino

There are two arduins, on one radio module for working with a computer via COM and an SD card. The second performs some of its functions.
Is it possible to first upload the sketch for the second arduino in some form to the SD card of the first, "firmware", and reflash the second arduino from it?

Answer 1

Yes, it's possible.

Answer 2

I googled one option, I think you need to start with it
arduino.ru/forum/proekty/sdelal-upnovlenie-program...