Done this twice and thankfully the 2nd time I had the sense to clone the SD card as a backup first.
I ran the full update, mostly to get the new firmware, give or take 100 updates were available. Not sure if everything else went off ok, stopped at the fact that my external drive had a drastic size reduction from 640GB to 14GB. Now I do not know enough about unix to try and troubleshoot this so I simply restored the backup but would like to actually run the update.
The drive is an NTFS USB mounted drive, now the mount works fine, if I connect the same drive to another machine then all's well, however connected to the Pi its empty and only 14GB. Its arch linux
Not really sure if that's enough info, can probably get more if needed but do not know what else I would need to give. I can imagine it being extremely time consuming to try run each update manually to figure out whats causing so a slightly smaller testing pool would be nice if anyone has any ideas or has run into this before.