BOOT1.EFI(8)            FreeBSD System Manager's Manual           BOOT1.EFI(8)

NAME

     boot1.efi - UEFI chain loader

DESCRIPTION

     boot1.efi has been deprecated and will be removed from a future release.
     loader.efi(8) handles all its former use cases with more flexibility.

     On UEFI systems, boot1.efi loads /boot/loader.efi from the default root
     file system and transfers execution there.  Some systems may need to use
     gptboot.efi(8) when loader.efi(8) cannot be used directly on the ESP (EFI
     System Partition).

Initialization

     Before looking for the boot device, boot1.efi does the following
     initialization

     o   Sets up the console using the default UEFI console routines.

     o   Discovers all possible block devices on the system.

     o   Initializes all file system modules to read files from those devices

Boot Device Selection

     boot1.efi uses the following sequence to determine the root file system
     for booting:

     o   If ZFS is configured, boot1.efi will search the for zpools that are
         bootable, preferring the zpool on the boot device over the others.

     o   If UFS is configured, boot1.efi will search all UFS partitions for a
         bootable partition.  It will prefer the lowest numbered bootable
         partition on the boot device over all other choices.  It will fall
         back to partitions on other devices if none are found.

     A partition is considered bootable if it can load /boot/loader.efi from
     it.  Command line arguments to the next boot stage are read from the
     first existing file of /boot.config or /boot/config in that order.

Caveats

     o   The order in which file systems are tried is undefined.

     o   No encryption support is available.

     o   There's no way to interrupt the boot process to select booting from
         some other location.

     o   When configuring a serial console for FreeBSD, but not for UEFI, no
         output will show up on the serial console from boot1.efi.

     o   There's no support for marking partitions as the preferred one.  See
         gptboot.efi(8).

     o   There's no support for boot-once functionality.  See gptboot.efi(8).

FreeBSD 15.1-STABLE-HBSD         April 6, 2021                    BOOT1.EFI(8)