There is a neat pdf document on how to transplant Nintendo 1st gen GBA SP (AGB-001) to NGPC. I checked several AGB-001 units, and all are very dim. Is there a better source for frontlight? I think long time ago Mash Mods was selling those, but he is gone. Any other sources?
You can use the frontlight of a AGS-001 screen only - AGS-101 has a backlit screen! I've done the mod from the pdf twice to 1st gen NGPCs, it's very anoying to have it lined up correctly and keep it dust free - but in the end you have a NGPC you can play with in the dark. Compared to today's standards it is dim but that doesn't matter. What matters is that the screen loses a lot of it sharpness and the picture gets blurry.