Most CFWs allow you to toggle between "Scaled" and "Original" aspect ratios. For GBA, "Original" looks best but will be smaller; "Scaled" fills the screen.
Some versions of this CFW struggle with screen tearing on the IPS model. Bitboy Pocket Gold Firmware fc3000 custom firmware
has limited CFW options compared to more powerful devices, but enthusiasts primarily use two main "ports" to improve performance. 1. Neotendo / OpenDingux (Linux Port) Most CFWs allow you to toggle between "Scaled"