Kidou Senshi Gundam: Flanagan Boone Senki

A new tragic tale from the "One Year War" unfolds. Flanagan Boone, a Zeon soldier, trained under his beloved Commander Garma Zabi, but then, the Gundam, the "White Devil of the Federation," appeared... A new story of the One Year War begins from the perspective of Flanagan Boone, who appeared in the famous episode "Across the Atlantic Ocean" (Episode 28) of the Mobile Suit Gundam anime!

(Source: Hero's, translated)