Apple Macbook Air M1 (apple-MacBookAir10,1)

Contributors

 * 1) Asahi Linux Project

How to enter flash mode
for DFU mode: https://support.apple.com/en-gb/guide/apple-configurator-2/apdd5f3c75ad/mac

Bootloader
According to Asahi Linux's Wiki, m1n1 is the bootloader for Linux kernel booting. m1n1 is the bootloader developed by the Asahi Linux project to bridge the Apple (XNU) boot ecosystem to the Linux boot ecosystem. = What it does(from their wiki) = Proxy mode enables a huge toolset of developer features, from reducing your Linux kernel test cycle to 7 seconds, to live hardware probing and experimentation, to a hypervisor capable of running macOS or Linux and tracing hardware accesses in real time while providing a virtual UART over USB. m1n1 can load U-Boot as a payload.
 * Initializes hardware
 * Puts up a pretty logo
 * Loads embedded (appended) payloads, which can be:
 * Device Trees (FDTs), with automatic selection based on the platform
 * Initramfs images (compressed CPIO archives)
 * Kernel images in Linux ARM64 boot format (optionally compressed)
 * Configuration statements
 * Chainloads another version of itself from a FAT32 partition (if configured to do so)

U-Boot
U-Boot is the default payload for m1n1 stage 2, and is used to provide a standard preboot environment familiar to AArch64 developers. External boot is not supported with the native Apple Silicon boot tooling, making U-Boot a hard necessity for providing a PC-like boot environment. It is able to boot from any external media (USB drive, network, etc.) and users an execute any EFI binaries.