Thema: Do I lose the images in multiboot if I flash online the main image with backup?

I think I need to reinstall the image in flash to fix a problem, so I'd like to flash it online with all settings and plugins backed up.
Never tried this before, so I'm hesitant, there are 5 more images (2 of them in sdcard), and I wouldn't want to lose them all after this procedure.
What kind of upgrade method would you suggest for the image in flash, in order to keep those in multiboot as well?

no nothing to lose