More info in: http://switchbrew.org/index.php?title=Package1 Downgrade check The bootloader will check if someone attempted to downgrade it. A fuse array will be checked, if too many fuses are burnt the bootloader will detect a downgrade attempt. The fuse array and the expected number of burnt fuses is different on unit type 0 (non-retail) and unit type 1 (retail). Panic The panic function does the following things: It clears the stack It disables(?) and clears the security engine It sets a fuse (so that Nintendo knows that you attempted to mess with the bootloader) It clears the key area It clears the data for stage 2 It signals over the debug interface that a panic occurred until the Switch is reset.