Emulation/Game Boy Advance

About Game Boy Advance
The Game Boy Advance is based on a 32bit ARM7TDMI CPU, and is relatively well understood.

Because the Game Boy Advance is relatively low spec, it can be emulated on most devices made since the early 2010's. However, the Game Boy advance is still a complex device, and so accurate emulation can still be taxing on hardware.

mGBA
mGBA is a newer Game Boy Advance emulator, and features superior speed and accuracy when compared to VisualBoyAdvance. It is open source software.

mGBA can work with Dolphin for GameCube-GBA emulation. mGBA also allows for eReader emulation.

Supported platforms for mGBA currently include Windows, macOS, Linux, Nintendo 3DS, Nintendo Switch, Wii, and PlayStation Vita. mGBA was made by developer endrift.

NanoBoyAdvance
NanoBoyAdvance is an open source Game Boy Advance emulator for Windows, macOS, and Linux developed by fleroviux.

VisualBoyAdvance
VisualBoyAdvance is an open source Game Boy Advance emulator from the mid-2000's. A more current fork, VBA-M, also exists.

Although VisualBoyAdvance (VBA) and a fork of VBA, VisualBoyAdvance-M (VBA-M), were once the best Game Boy Advance (GBA) emulators, they have been since surpassed by mGBA. VBA-M supports connections with Dolphin for GameCube-GBA emulation. While both are still good emulators, mGBA is superior in practically every way.

VBA is no longer in development and has a known security flaw allowing arbitrary code execution. This means it is especially critical that users only use known good backup files made by themselves when using VBA.

No$GBA
No$GBA is a freeware (Gratis) Game Boy Advance and Nintendo DS emulator.

GBE+
GBE+ (Short for GB Enhanced +) is an open source emulator for most portable Nintendo handhelds of the 2000's, including the GameBoy Advance. GBE+ is most notable for supporting the emulation of a number of obscure add ons.

Making backups
There are a variety of methods to make backups of the Game Boy Advance BIOS, game cartridges, and save files.