Boot Raspberry Pi4 with custom boot loader, linux, shell and utilities:

• ARM Trusted Firmware
• UEFI
• Linux
• Mksh (Shell)
• Utilities (Toybox)

1. Format GPT and create 3 partitions:
   • sudo cgdisk /dev/disk/by-id/<usb-drive>
     • part1 (EFI system partition)
     • part2 (Linux swap)
     • part3 (Linux filesystem)
2. Format file systems
   • sudo mkfs.vfat -F 16 /dev/disk/by-id/<usb-drive>-part1
   • sudo mkswap /dev/disk/by-id/<usb-drive>-part2
   • sudo mkfs.ext4 -N 803200 /dev/disk/by-id/<usb-drive>-part3

1. Sync: sync.sh
2. Build: build.sh
3. Use udisksctl to:
   • Copy /sdcard to /dev/disk/by-id/<usb-drive>-part1
   • Copy /rootfs to /dev/disk/by-id/<usb-drive>-part3

• Supports 1024x600 LCD; remove hdmi* entries from config.txt if not desired
• rootfs is mounted r/w

• Forked from original project: RPi4
• https://www.linuxfromscratch.org
• https://landley.net