I agree with Martin and others that uploading your brain is not a viable alternative. At what age do you upload, before [brain cells start dying ar age 25?)?
I interpret the original question (and most hypotheticals like this) not to refer to now ("...IS a viable alternative") but to whether such a thing will be possible in the future with more advanced technology.
Is there is some theoretical barrier or insuperable obstacle that will always be impossible to overcome no matter what the technology?