Freebsd – How to Pass High Resolution from GRUB2 to FreeBSD

I haven't tried this, but you might be able to boot FreeBSD if you first create a BSD disklabel on the disk.

I strongly recommend reading the Linux + FreeBSD howto for information about BSD and Linux partitions before doing anything else. I'll explain what to do with fdisk as it's closer to the metal.

You may be able to perform the actions below from Parted; I don't know if its support for BSD partitions is up to the task. I advise you to try Parted before fdisk as it's less error-prone.

First, from Linux, create a BSD partition table. Run fdisk /dev/sda (or whichever disk you want to install FreeBSD on) and:

1. Create a PC-style primary partition (one of /dev/sda1 through /dev/sda4) with the n command. It will contain everything from FreeBSD, so size it adequately.
2. Set its type to a5 (FreeBSD) with the t command.
3. Create a BSD disklabel on the newly created partition with the b command.
4. Create (with the n command) a BSD partition a that uses part of the space allocated to FreBSD; typically the a partition starts 64kB after the beginning of the BSD space. This is the root partition. Set its type (with the t command) to 7 (4.2BSD).
5. Create a BSD partition b that uses part of the space allocated to FreeBSD. This will be the swap partition; set its type to 1 (swap). I think this step is optional.
6. Remove the d partition that Linux's fdisk created.
7. Use the x command to create a BSD partition d that coincides with the partition where you've stored the FreeBSD installation file.
8. Review your changes very very carefully. If you're satisfied, run w to write the new BSD disklabel to disk, and run w again in the main menu to write the PC partition table to disk.

Note that this is all very error-prone; a typo could destroy all your data. Again, if Parted can do this, use Parted.

Once you've created BSD partitions, try method #2 or method #3 again.

After 4 years... :)

Try this:

menuentry 'menuentry' {
    set root=(hd0,1)
    syslinux_source /path/isolinux/isolinux.bin
    syslinux_configfile /path/isolinux/isolinux.cfg
}