Many of you can ignore this post as I am sure you are already fully understanding Korg's terminology.
It is important to understand what Korg means by the terms "Write, Save, Load, Backup, Restore"
When explaining a problem or asking/answering a question it can get very confusing on both sides at times and end up with cross-purpose discussions.
So, in summary:-
- Write - write into internal memory only (can appear in many different modes/menus)
Save - save internal memory data onto physical media (USB, HDD, mSD, SSD) - MEDIA mode (e.g. related to ".SET" or part of)
Load - load from physical media (USB, HDD, mSD, SSD) into internal memory - MEDIA mode (e.g. related to ".SET" or part of)
Full Resource Backup - create a full resource ".BKP" file (internal memory including factory data) onto physical media (USB, HDD, mSD, SSD) - MEDIA mode
Resource Restore - restore from a full resource ".BKP" file (includes factory data) into internal memory from physical media (USB, HDD, mSD, SSD) - MEDIA mode
Factory Restore - restore PA4X resources to current OS level factory defaults (this is like a keyboard factory reset) - no specific files involved - MEDIA mode
I hope this helps (trust me, I fall into this "terminology" trap too often)
All the best
Pete

Just a footnote point - EXAMPLE:- if you "Full Resource Backup" in OS 1.2.1, DO NOT "Resource Restore" that ".BKP" after any OS upgrade unless the OS update release notes specify.