cmd:guf: Add ENV mode to bootselect
Added a fallback environment mode for the bootselect mechanism. By now, we have some devices that don't equip compatible RTCs. On these devices, the bootselect command doesn't work in the current form.
Added a fallback environment mode for the bootselect mechanism. By now, we have some devices that don't equip compatible RTCs. On these devices, the bootselect command doesn't work in the current form.