GHost BSD rewrote HDD bootblock eliminating GRUB

MMako

Putting into context :
I have several HDDs with crossed GRUB2 entries.
In one of those HDD have some Linux distros and today tried to manually install GhostBSD.

In the installer I defined the manually the needed partitions ( 1 root, 1 boot , 1 swap )
and did not touch any of the others.

Everything apparently were accepted and installed after rebooting GhostBD boots up correctly.
Although No more Grub entries only the Ghost BSD boot menu options.

I was expecting to have the Grub Menu without the GhostBSD entry but it seems that GhostBSD
simply wrote the bootblock...

The aforementioned Linux are working and valid via another HDD ( os-probe finds some of them) ...

What are my options to boot the other Distros ?

An interesting bit :
In linux I sda ├─sda1 ext4 ├─sda2 ext4 ├─sda3 ext4 ├─sda4 swap ├─sda5 ext4 ├─sda6 ext4 ├─sda7 xfs ├─sda8 ├─sda9 exfat ├─sda10 ext4 ├─sda11 ext4 ├─sda12 xfs ├─sda13 btrfs ├─sda14 ext4 ├─sda15 ext4 ├─sda16 vfat ├─sda17 ext4 ├─sda18 └─sda19 zfs_member sdb ├─sdb1 ntfs ├─sdb2 ntfs └─sdb3 ntfs have this partition structure:

rootantiX23 b8d54c76-74b3-4413-8efa-12770467b3f4
4cbb7c3f-6c69-4b5a-bb62-5f62a03b481e
deb13 6c8b8fea-f9cf-46ae-8d2c-a9b561fddfaa
735b92c7-7227-46a5-9aee-858b7c4bbe47
rootMX23 34472c72-251c-4c41-80d4-e682c37b3e37
oracle 8e5eeec1-ca28-4877-bf1b-d30f461a190c
ebb68b66-adaf-4028-b12c-e18d637ee5e6

Masseffect 75EF-34CF
a7b2eca7-120e-449f-ac26-3bbfba1989fd 4,8G 76% /
572224bc-a8f5-4fd5-89e9-403dd1491c8c
Alma 9eddaf81-c6e4-46b1-b963-2957992c9121
OpenSuse 42ed422d-73bd-401c-93a1-d1d0c7b0ed87
83bac3cb-72e9-456a-81cf-cb04a5e8ec14
a5bccf02-b980-4177-a4c8-77396f380dfd
ESP D720-6074
root 1c089865-dfc7-488a-80ba-aea142b859e9

zroot 7513022252329279599

System Reserved 5C1A1A261A19FDA8
DC5E38D75E38ABE0
5864F4DC64F4BDB6

whereas
GhostBSD is in partition sda19 ( Zfs /Zroot)
a strange sda18 is defined as unknown but were defined as /boot
a sda8 is a GRUB2.core.img
All the others are other distros ...

Am I able to add them in the GhostBSD menu ?

vimanuelt

Select rEFInd during the install process.

MMako

vimanuelt
I saw and thought about that option but the installer kept "refind" unavailable ( grey button ) and un-selectable.

Nonetheless what can I do now without loosing GhostBSD install ?
How can I had to the HDD any of the other systems ?

vimanuelt

You may need to enter your system's BIOS and look for the boot option to select UEFI instead of Legacy.

MMako

Just to clarify..
My system boots in BIOS Mode only.
Almost all the distros boot in BIOS mode .

My question now is : how can I add the existing distros ( as shown in the initial detail ) to the GhosBSD Menu ?
Or do I need to rewrite the GRUB2 bootblock and then add GhostBSD entry ?

vimanuelt

Iirc, in legacy BIOS mode the correct way to boot from GRUB is to chainload the FreeBSD boot sector, not to load a kernel. Since GhostBSD is installed on sda19, GRUB will normally see it as (hd0,msdos19). The reliable approach is to add a manual entry that sets the root to that partition and uses chainloader +1. This keeps GRUB in control of the disk while handing off execution cleanly to the FreeBSD loader, which then handles ZFS and GhostBSD boot environments. After adding the entry, you regenerate the GRUB configuration with update-grub or grub-mkconfig -o /boot/grub/grub.cfg, depending on your distribution.

If disk ordering is not stable on your system, you can verify the correct mapping from the GRUB command line by listing available disks and partitions with ls and checking which (hdX,msdos19) actually contains a filesystem. A UUID based GRUB entry is also possible using search --fs-uuid, but this only works reliably if GRUB can read the filesystem on that partition, which is not always the case with ZFS backed FreeBSD installs. For that reason, direct chainloading by disk and partition number remains the most predictable and widely supported solution in BIOS mode.