Simplifying Bootloader Entry for LED Badge Magic Devices

The Badge Magic device has a hardware constraint that makes firmware updates nearly impossible for most users after first flash. The onboard battery prevents a Power-On Reset, permanently closing the bootloader entry window after first boot. The only existing workarounds — desoldering the battery or shorting a capacitor are unsafe and unsuitable for workshops. This project implements a Stage-1 Gatekeeper that intercepts the boot sequence before any GPIO reconfiguration occurs, checks a retention SRAM location for a magic value, and jumps to the ROM bootloader if triggered. Three entry paths are provided: a USB vendor command, a button press pattern, and the existing first-boot hold — all safe, easily repeatable and requiring no hardware intervention.