Thanks for the suggestions!
Here is what did that worked for me. Hope it can be helpfull for others too.
Switched the grub2 to Fedora, running the ISO DVD > install > upgrade current version. This has restored the grub on FC. With grub on FC, it has recognized Ubuntu automatically, i.e. the dual boot is working now.
Then, the only missing piece was the OpenBSD to get the triboot running. Performing the next steps solved it:
Code:
# yum install os-prober
# gedit /etc/grub.d/31_openbsd
In the file 31_openbsd include
Code:
#!/bin/sh -e
echo "Adding OpenBSD to GRUB 2 menu"
cat << EOF
menuentry "OpenBSD" {
set root=(hd0,1)
chainloader +1
boot
}
EOF
save the file... then on terminal:
Code:
# chmod 777 31_openbsd
# grub2-mkconfig -o /boot/grub2/grub.cfg
Reboot and enjoy your triboot with grub2.