add haiku in grub2 also make bootable stick after build

I have made the bootable stick this way after my generic image finished

cd haiku/generated
dd if=haiku.image of=/dev/sdb
sync

add the next entry in grub2

sudo gedit /etc/grub.d/40_custom

for me the partition prepared is /dev/sda3

menuentry "Haiku" {
    set root=(hd0,3)
    chainloader +1
}

then update the grub config

sudo update-grub