# freebsd-boot partition



## bachmarc (Mar 15, 2016)

Hello,
I seem to be confused now...

I thought booting starts with MBR or GPT and a tiny little piece of code inside... pointing to loader in /boot to launch kernel and further on mounting /...

In addition I thought in case of UEFI boot the GPT points to a small UEFI disk which then loads a bootmenu and points to loader/kernel....

And yes in a test vmware I found the installer to create a tiny slice with *freebsd-boot* type beside a bigger /boot and a huge /

=> Ok, I thought:" ok it is UEFi in vmware player! " But no... I got to know that I have to enable uefi in vm config file and after doing this, the OS is not booting anymore.

=> I turned out that I am not booting UEFI style... but what the hell is the tiny 64K slice for? it is of type *freebsd-boot* and I cannot mount it as FAT16...

What I have missed? Is this slice home of stage 2 code which is not fitting in GPT header?


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## kpa (Mar 15, 2016)

It's a "raw" partition without any filesystem on it and it contains the boot code for BIOS boot on GPT disks. I have no idea if a real UEFI installation needs or uses it because none of my systems use UEFI. It is essentially installed by a process that does the same as `# dd if=/boot/gptboot of=/dev/ada0p1` would do.


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## wblock@ (Mar 15, 2016)

The MBR or PMBR is only 512 bytes, and some of that is taken for the partition table.  There just is not enough room for non-trivial boot code.  So FreeBSD has always split up the boot loader.  See https://www.freebsd.org/doc/en_US.ISO8859-1/books/handbook/boot-introduction.html.


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## tingo (Mar 17, 2016)

And UEFI doesn't need this boot partition.


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