During the One Year War, the Earth Federation developed a system of interchangeable modules known as the G-Parts. These allowed rapid transformation of the unit to adapt to different combat conditions, even when it was out in the battlefield.
The G-Parts had an Easy Mode to allow them to operate without the Gundam torso, so they could continue playing a support role to the Gundam during battle. The G-Bull Easy was the standalone version of the G-Bull.
The G-Bull was the combination of the RX-78-2 Gundam with the Core Block System modular units, known as the G-Parts. There were two sets of G-Parts: the A-Parts and the B-Parts. A-Parts consisted of a nose with a canopy cockpit, a set of caterpillar treads, and a pair of beam cannons. The B-Parts was a fuselage with four thrusters.
The G-Bull Easy was the G-Bull in the Easy Mode. This meant that that G-Parts operated without the Gundam torso. It was controlled by one pilot, compared to two in the G-Bull. This made it more taxing on the pilot, who had to handle the firing of the cannons.
The G-Bull Easy was armed with beam cannons and missile launchers for ranged attacks. These were mounted on the A-Parts modular unit of the support tank. It could equip the optional beam rifle, which was held by the Gundam.
There were a pair of beam cannons mounted on the top of the A-parts modular unit, just behind the canopy cockpit. The cannons could operate longer in the G-Bull Easy configuration compared to the G-Fighter because of the additional generator from the Gundam torso.
The G-Bull Easy was mounted with two RX*M-Sh-008/S-01025 (Renpou eXperimental Medium Shield) shields, one on each side. Renpou means Federation in Japanese.
The shield was able to block most ballistic and explosive projectiles.
Behind the scenes
Kunio Okawara was the original mechanical designer.
The G-Bull Easy only appeared in the Mobile Suit Gundam anime series. It was removed in the compilation movies, because Yoshiyuki Tomino wanted to make the movies closer to his vision of for the series. So elements that were considered closer to the super robot genre were replaced with real robot elements.
However, Yoshiyuki Tomino felt that the G-Bull Easy was considered closer to the super robot genre, instead of the real robot genre that he envisioned for the series. Thus, the G-Bull Easy was removed in the compilation movies.