There are 4 location entries accessible via either faction's fleet. These codex entries are not required for any achievements.
The Alliance Intelligence Report: Attack on the Senate Tower codex entry hostile.
Codex type: Locations
Codex location: Works Control Room
Codex coordinates: 1170, 4694
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission 'Uprising: Divided We Fall' to obtain this codex entry
The Colicoid Creation Nest codex entry proximity location.
Codex type: Locations
Codex location: Battleground: Contestant Processing
Codex coordinates: -140, 96
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission '[FLASHPOINT] Colicoid War Game' to obtain this codex entry
The Hammer Station codex entry proximity location.
Codex type: Locations
Codex location: Hammer Station: Expansion Excavation
Codex coordinates: 401, -836
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission '[FLASHPOINT] Hammer Station' to obtain this codex entry
The Temple of the Ancients codex entry proximity location.
Codex type: Locations
Codex location: Temple of the Ancients
Codex coordinates: -898, -755
Faction: Both
Class: Bounty Hunter - Imperial Agent - Jedi Consular - Jedi Knight - Sith Inquisitor - Sith Warrior - Smuggler - Trooper
Associated Achievement: None
Special Requirements: You must progress the mission '[FLASHPOINT] Legacy of the Rakata' to obtain this codex entry