[mk01]

in general yes. but the same way as with BIOS (or UEFI) some actions started / performed during that pre-boot have consequences later.

that means it is wanted to have a mechanism for it's update adhoc. look at cubox forums how big issue / problem u-boot instalation is for regular user. so I decided since 1st image that uboot will be part of kernel updating with it.

of course we can discuss if it makes sense re-flash 1MB each time with kernel even if uboot is not changed - and that one can be adapted in the postinst scripts - but that is more about the mechanism rather then why do we update it in general.