I was having the same problem. My Nintendo DS NTR 001 showed white screens after showing the Nintendo DS logo. I found out you can boot directly into a DS cartridge by holding ABXY + R, or directly into a GBA cartridge by holding ABXY + L, while powering on. Doing so, I was able to run a cartridge with noflashme to reinstall the stock firmware. I believe the data retention on the flash chip may have reached the end of its lifecycle being almost 20 years old and required a refresh. EDIT: It says online using noflashme is not recommended for DS Lite. The DS I fixed was the original DS. Also, I wanted to clarify that I did not have flashme installed. I just used the tool to reinstall the stock firmware.