Warning: os-prober will not be executed to detect other bootable partitions

[pobrn]

@jmak

Warning: os-prober will not be executed to detect other bootable partitions.
Systems on them will not be added to the GRUB boot configuration.
Check GRUB_DISABLE_OS_PROBER documentation entry.

os-prober has been disabled by default, you need to uncomment/add

GRUB_DISABLE_OS_PROBER=false

to /etc/default/grub and run sudo update-grub.