You can't mess your system up with that one; if you're not root, it fails, and if you are root, it works.

The ask:immc2, of course, selects that it will prompt with the menu, and that it will default to immc2; even if, for example, you're confused and it's really the external card, it'll still ask, and you can just go to the right one in the menu. Even if you completely trash the ask, too, it'll still let you hold the menu key down, and you can get back in and try again. Don't worry.

So start xterm, sudo gainroot, chroot /mnt/initfs cal-tool -R ask:immc2, done.