# Should I continue to install , keep two efi partition for dual boot?



## freeink (Dec 8, 2019)

Installed Debian  buster,10.2 for entire disk.
Then resized the last home partition sda4, Left 112G unallocated partition for FreeBSD to install
Debian have a 512M efi, FreeBSD guided  partitioning tool will create another 200M efi ,
keep both the Linux and FreeBSD efi partitions?


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## freeink (Dec 9, 2019)

menuentry "FreeBSD-10.3 /boot/loader"{
                insmod ufs2
                set root=(hd0,gpt6)

                kfreebsd /boot/loader

        };

can not boot to  FreeBSD , end it up with many small black rectangle dots


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## freeink (Dec 9, 2019)

How to slice unallocated partition into "ada0p5a and ada0p5b"  instead of  "ada0p5 and ada0p6"


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## Phishfry (Dec 9, 2019)

Two different disk schemes here. You cannot mix and match. Either MBR or GPT scheme.
ada0p5 is a GPT scheme.
ada0s5a would be an MBR scheme.

You could either use the debian EFI partition for the boot files (and use grub2 to choose what to boot) or create a FreeBSD EFI partition on ada0p5 and then use ada0p6 for the installation and use the BIOS to choose what to OS boot. The BIOS will detect the two different /BOOT/BOOT.EFI files.
This will need to be installed by hand as the FreeBSD installer wants the whole disk.
You can drop to a shell during the partition phase of the install and do this I believe. This is not a very easy task.


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## freeink (Dec 9, 2019)

"update-grub  /dev/sda"  not working            "chainloader +1"  not working
must manually edit /boot/grub/grub.cfg
The following configuration did the trick:

menuentry  "freeBSD" {

insmod ufs2
set root=(hd0,gpt6)
chainloader /boot/loader.efi

}

### END  /etc/grub.d/40_custom ###

if miss ".efi" will cause error cannot load image.


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## freeink (Dec 9, 2019)

Thanks Phishfry, spent another night in motel to fix this.

kfreebsd  /boot/loader.efi  not working will cause "error:invalid a.out header."

If do not keep FreeBSD partition tool 200M efi ,  I guess can omit the ".efi"

insmod ufs2
set root=(hd0,gpt6)
chainloader /boot/loader


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