Looking for an explanation of what a "Profile Update" and a "PRL Update" are

Simply

http://www.phonescoop.com/glossary/term.php?gid=11

PRL

(Preferred Roaming List)

The PRL is a list of information that resides in the memory of some kinds of digital phones. It lists the radio frequencies the phone can use in various geographic areas.

The part of the list for each area is ordered by the bands the phone should try to use first. Therefore it's a kind of priority list for which towers the phone should use.

The PRL helps determine which home-network towers to use, and also which towers belonging to other networks to use in roaming situations (areas where the home network has no coverage.) When roaming, the PRL may instruct the phone to use the network with the best roaming rate for the carrier, rather than the one with the strongest signal at the moment.

Since a PRL tells the phone "where" to search for a signal, as carrier networks change over time, an updated PRL may be required for a phone to "see" all of the coverage that it should, both with the home network and for roaming.


The profile is the user Data profile, I have always thought of it as a log in to the data network. Refreshing signs ya out and back in. (just my own terminology)

there is a significantly more in depth description on XDA somewhere I just have to find it.

 

Most phones today update their roaming lists automatically. With most smartphones and 4G LTE devices it's not recommended to manual update prl and some who have have had data connectivity issues.

 

That's carrier specific - what you said is generally true for Verizon.

The exact opposite is true for Sprint.

This covers the prl definition well with a Sprint focus - http://s4gru.com/index.php?/blog/1/entry-338-what-is-a-prl/

Your profile id is basically your carrier login id.