If you didn't mess with your Sys:MorphOS/ Directory then updating the OS is the easiest thing. You simply have to rename the MorphOS directory to something else (MorphOS_ i.e.) and copy the one from 1.4 to your Sys: Partition et voila: done.

Many people are confused at first with the system of having a sys: and a Mossys:, but after 2 or 3 os Updates you won't want to miss it anymore.