Boycott Advance is a capable free and portable GBA Emulator that has been ported across several systems, ranging from Windows to Linux.
It is able to emulate commercial ROM’s along with homebrew successfully. However, don’t expect the best emulation, performance should be fine as it was developed for much older Pentium systems.
For some time Boycott Advance failed to emulate sound, it was until after the release of version 0.2.1 did the GBA emulator start to actually to be able to support sound.
Development of Boycott Advance has sadly come to a stop and hasn’t seen in progress for over 13 years. However, it still remains a capable emulator and worth checking out, even if it has now been surpassed by many other emulators such as VBA-M and higan. It is certainly still worth a download.