Jetson Xavier NX build how to setup jetson only to work with external ssd later on?

I am trying to figure out how to setup a new jetson NX to be able to boot from external SSD. I only want the part that flashes the jetson with bios , because the SSD drives i work with allready come with l4t ,Jetpack and additional data on them.

which jetpack version is in use?


sdkmanager can flash to SSD directly.

The SSD isn’t the problem , i get the ssd’s from a third party when they already contain an image with the l4t OS ,Jetpack and my product’s software. So what i want to achieve is being able to plug the ssd and the jetson will automatically boot from it. to do that i understand i need to flash the jetson somehow but not load an operating system on it.
I only want the jetson to contain what is necessary for it to be able to boot from external SSD.