Does the question mark, point you to how/where to turn off the bootloader option?
A bootloader, is used to low-level re-load software into a device. Quite often after a failure of a higher-level update.
Assuming all is well/working, and you have done a full shutdown, power-off, recite Mary had a little lamb.. Power-up?
Then I would follow the breadcrumbs, and turn the bootloader off. - I would guess it is a belt and braces approach to the update, which means if it has gone horribly wrong, there is a way to recover?
Failing that, an email to Marklin..
PhilP