Amiga 500 Plus

The Commodore Amiga 500 Plus (often A500 Plus or simply A500+) is an enhanced version of the original Amiga 500 computer. It was notable for introducing new versions of Kickstart and Workbench, and for some minor improvements in the custom chips, known as the Enhanced Chip Set (or ECS).
Introduction.
The A500+ was released in several markets (including many European countries), but was never sold officially in the U.S.
Although officially introduced in 1992, some Amiga 500 Plus units had already been sold (masquerading as Amiga 500 models, and with no prior announcement) during late 1991. It has been speculated that Commodore had already sold out the remaining stocks of Amiga 500s, before the run-up to the profitable Christmas sales period. In order to make enough A500s before Christmas, Commodore used stocks of the new 8A revision motherboards destined for the A500+. Many users were unaware that they were purchasing anything other than a standard Amiga 500. Although the Amiga 500+ was an improvement to the Amiga 500, it was minor. It was discontinued and replaced by the Amiga 600 in summer 1992, making it the shortest-lived Amiga model.
Reason for design.
Commodore created the A500+ for a couple of reasons. The first was cost reduction; minor changes were made to the motherboard to make it cheaper to produce. It was also so that Commodore could introduce the new version of the Amiga Operating system, 2.04.
Compatibility problems.
Due to the new Kickstart, quite a few popular games (such as Treasure Island Dizzy, SWIV, and Lotus Esprit Turbo Challenge) failed to work on the Amiga 500+, and some people took them back to dealers demanding an original Kickstart 1.3 Amiga 500. This problem was solved by third parties who produced Kickstart ROM switching boards, that could allow the Amiga 500+ to be downgraded to Kickstart 1.2 or 1.3. It also encouraged game developers to use better programming habits, which was important since Commodore already had plans for the introduction of the next-generation Amiga 1200 computer. A program, Relokick, was also released (and included with an issue of CU Amiga) which loaded a Kickstart 1.3 ROM image into memory and booted the machine into Kickstart 1.3, allowing incompatible software to run. In some cases, updated compatible versions of games were later released, such as budget versions of Lotus 1 and SWIV. Double Dragon 2 by Binary Design received an update for ECS machines with the "Amiga phase-alternated linescan version 4.01/ECS". This solved compatibility issues with the graphics which appeared garbled on ECS machines, and it also slashed the in-game loading times from around 20 seconds to just over 6.