update USB?

[Mr-Protocol]

How do you do an update to a USB installed BT4 to have the current update repositories?

Also when will the actually ISO image be updated? Kinda of fuzzy on how things are updated with BT4

[Archangel-Amael]

How do you do an update to a USB installed BT4 to have the current update repositories?

Also when will the actually ISO image be updated? Kinda of fuzzy on how things are updated with BT4

If you have an official copy of BT4 final and have not changed your apt-sources file then you have the correct repositories.
As for upgrading it is a matter of using apt-get. There is help in the man page on it or see here. As for actually updating a package it would generally be something like apt-get update&& apt-get package-name.
This would update the package cache and then grab the latest version of said package from the repo.