freebsd: Document how to build UEFI app on FreeBSD

[JohnAZoidberg]

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[JohnAZoidberg]

@aokblast is there a scripted way to format a disk image on FreeBSD?
On Linux I used GNU parted.

[aokblast]

Hello, we have gpart which is the abbriviate of geom part that enable you to create and add partition. I found a post on stack exchange that have examples about this. Do I answer your question?

[aokblast]

Oh, you are talking about image. We have mkimg which can be used as following pattern (stolen from my previous commit :) )

cfgdirname=$(mktemp -d /tmp/config.XXXXX)
cp ${BASEBITSDIR}/etc/bsdinstall.example ${cfgdirname}
makefs -D -B little -t msdos -o fat_type=16 -o volume_label=CONFIG -o create_size=16m ${2}.config ${cfgdirname}

mkimg -s mbr \
    -b ${BASEBITSDIR}/boot/mbr \
    -p efi:=${espfilename} \
    -p freebsd:-"mkimg -s bsd -b ${BASEBITSDIR}/boot/boot -p freebsd-ufs:=${2}.part" \
    -p fat16b:=${2}.config\

[JohnAZoidberg]

oh! That's cool. That looks super easy!

[JohnAZoidberg]

Haven't tried, but might be as simple as this:

$(BUILD)/boot.img: $(BUILD)/boot.efi
  mkimg -s gpt \
    -p efi:=$<

But how can I use different make rules on FreeBSD 🤔

[aokblast]

What is the make rules you mentioned? Could you give me some detailed example?

[aokblast]

Oops, I forget some code segment. You have to create a partition image by mkfs than put file into it by directory. After that, you can use mkimg to create a full disk image. Here is a patch use this feature. You can take a release/amd64/make-memstick.sh as example. Hope I answered your question.

[JohnAZoidberg]

Done! Now we just need to make sure it uses different commands on linux vs bsd