Upgrading boot from GPT(BIOS) to GPT(UEFI)

[Warren Block]

On Fri, 16 Dec 2016, Eric van Gyzen wrote:

> On 12/16/2016 11:08, Fernando Herrero Carrón wrote:
>> Hi everyone,
>>
>> A few months ago I got myself a new box and I have been happily running
>> FreeBSD on it ever since. I noticed that the boot was not as fast as I had
>> expected and I've realized that, while my disk is GPT partitioned, the boot
>> process is still BIOS based:
>>
>> % gpart show
>> =>       34  976773101  ada0  GPT  (466G)
>>          34          6        - free -  (3.0K)
>>          40       1024     1  freebsd-boot  (512K)
>>        1064        984        - free -  (492K)
>>        2048   67108864     2  freebsd-swap  (32G)
>>    67110912  909662208     3  freebsd-zfs  (434G)
>>   976773120         15        - free -  (7.5K)
>>
>> I am reading uefi(8) and it looks like FreeBSD 11 should be able to boot
>> using UEFI straight into ZFS, so I am thinking of converting that
>> freebsd-boot partition to an EFI partition, creating a FAT filesystem and
>> copying /boot/boot.efi there.
>>
>> How good of an idea is that? Would it really be that simple or am I missing
>> something? My only reason for wanting to boot with UEFI is faster boot,
>> everything is working fine otherwise.
>
> I would recommend creating another partition for EFI instead of replacing your
> freebsd-boot partition, in order to have a working fallback in case EFI boot
> doesn't work.  You would need to steal some space from your swap partition.

Be aware that some newer Dells really don't like to have both and will 
refuse to boot in either mode with such a setup.