GBA:Game Boy Advance Model Differences
Page content & researching collaboratively taken from io55.net's Game Boy Advance page with permission.
There are four Game Boy Advance models, and one revision of note within the original GBA.
Models & Revisions
Models are arranged chronologically. Revisions are listed under their respective model.
Game Boy Advance - AGB-001 (2001-2003)
The very first GBA, and possibly the most common one. Easily identified by its moderately-sized rectangular-ish shape, and the “Game Boy Advance” text on the bezel. Features no screen light, a headphone jack, and compatibility with a variety of accessories and add-ons. One important note about these add-ons, is that a significant quantity of them are designed in a way that makes them impossible to use on any SP or Micro system - mostly third party accessories. For this reason alone, the original GBA system holds water nowadays, and its shape and ergonomics may be more appealing than the SP's for certain people. Modding these systems is relatively simple, although there are differences between motherboard screen pins (required for a backlit screen) that are important to know - they have been noted under this entry.
32-pin vs 40-pin in original GBAs
The difference between pins impacts the way one mods their original GBA's screen. In the past, 32-pin vs 40-pin meant that some systems got the shorter end of the stick when it came to modded screen brightness and quality, but nowadays, these issues have been eliminated, making 32 vs 40-pin only impact the cable one should buy online.
Game Boy Advance SP - AGS-001 (2003-2005)
Nintendo's first model change for the GBA line, and certainly a welcome one in some aspects. Easily identified by its clamshell design that can be opened and closed. Major changes include the aforementioned radical shift in shape, the removal of the headphone jack and the introduction of a screen light. However, the screen is lit from the front, which is an improvement but certainly not a definitive improvement. With this addition, a button to turn the frontlight on or off was added below the screen on the system's lower half. In regards to the removed headphone jack, an external adapter which plugs into the charging port (which also carries analog audio) is required to use conventional headphones with the SP.
Game Boy Advance SP - AGS-101 (2005-2009)
Normally, the AGS-101 would be considered a revision. However, it has been included as a separate version due to its externally significant changes that can be identified with ease.
Very similar to the AGS-001 SP but has a backlit screen replacing the frontlit model. While identifying any GBA SP is very easy, specifically identifying an SP as a 101 can be slightly more difficult. Luckily, the underside of any GBA SP will distinguish between if it's a 001 or 101 - simply check the model number on the sticker. If this is unavailable, look at the screen - a 101's turned off screen will be almost perfectly black, while a 001's turned off screen will have a green-greyish tinge, similar to an original GBA or GBC. Of course, if the screen is on, games will look very vibrantly colored and tremendously bright. Outside of all this, however, the 101 is essentially the same as the 001, but this one change is enough to make the 101 a definitive buy for the most part.
Game Boy Micro - OXY-001 (2005-2008)
The smallest, rarest, most expensive, and potentially most interesting of the GBAs. Easily identified by its small shape and interchangeable faceplates. Due to its radically different shape and size, the Micro is not compatible with almost all GBA accessories, including link cables (a special Micro-compatible link cable exists). Similarly, the Micro is not compatible with any GB or GBC titles - only GBA. Despite these major removals, the Micro's tiny size, bright and vibrant screen with greater sharpness, and customizable faceplates certainly hold appeal. One benefit of the Micro over the SPs is the reintroduction of the headphone jack.