Comment 16 for bug 1845289

For the sake of testing I've updated to the latest grub from 19.10 (2.04-1ubuntu12) and I can't boot Windows anymore. My exact steps were:

0. Ubuntu 19.10 with grub from 19.04. Everything works
1. Move /etc/grub.d/07_os-prober back to /etc/grub.d/30_os-prober to rule this change out
2. sudo apt update && sudo apt dist-upgrade
3. sudo grub-install /dev/sda
4. sudo update-grub
5. Reboot
6. Can't boot Windows anymore

I've compared grub config from 2.02 to 2.04. They look almost exactly the same. The only differences are:

- set vt_handoff=vt.handoff=1
+ set vt_handoff=vt.handoff=7

and

+### BEGIN /etc/grub.d/10_linux_zfs ###
+### END /etc/grub.d/10_linux_zfs ###

Windows part config:

menuentry 'Windows Boot Manager (on /dev/sda1)' --class windows --class os $menuentry_id_option 'osprober-efi-CAC2-FF0C' {
 insmod part_gpt
 insmod fat
 set root='hd0,gpt1'
 if [ x$feature_platform_search_hint = xy ]; then
   search --no-floppy --fs-uuid --set=root --hint-bios=hd0,gpt1 --hint-efi=hd0,gpt1 --hint-baremetal=ahci0,gpt1 CAC2-FF0C
 else
   search --no-floppy --fs-uuid --set=root CAC2-FF0C
 fi
 chainloader /EFI/Microsoft/Boot/bootmgfw.efi
}

I've recorded video of boot process with "set debug=all" grub config. Send me a message through https://launchpad.net/~xeron-oskom/+contactuser if you want to see it.