You cannot (easily) modify the BootROM itself. However, having a full dump of it allows developers to:
Press to go back to the main menu, then navigate to [0:] SDCARD .
The boot9.bin was the subject of intense scrutiny which led to the discovery of the and boot9strap exploits.
He leaned back, the blue glow of the monitor reflecting in his eyes. The 3ds wasn't a closed box anymore. It was an open book, and he had just turned to page one. 🔍 What is boot9.bin?