No grub boot menu after installing Mint dual boot with Legacy BIOS setting

[adam4235]

I have an Acer Aspire E 15 laptop. I had Windows 10 on one hard drive from my old computer which I cloned to a new, larger hard drive. My BIOS was set in Legacy (not UEFI) mode, and Windows worked in that mode. Then I installed Mint, using the option "install alongside Windows". After installation, it directly booted into Mint, but there was no Grub menu on boot so no way to boot to Windows. I was able to fix it by running Boot Repair from the Live USB using the automatic settings - but it should not have been necessary to do so. Whatever Boot Repair did to fix the issue should have happened during installation. See the attached file below for the output from Boot Repair.

The original hard drive that was cloned looks like this, from fdisk:

adam>sudo fdisk -l /dev/sda
Disk /dev/sda: 447.13 GiB, 480103981056 bytes, 937703088 sectors
Disk model:  SA400S37480G   
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0x59d38595

Device     Boot     Start       End   Sectors   Size Id Type
/dev/sda1  *         2048    104447    102400    50M  7 HPFS/NTFS/exFAT
/dev/sda2          104448 936661644 936557197 446.6G  7 HPFS/NTFS/exFAT
/dev/sda3       936663040 937697279   1034240   505M 27 Hidden NTFS WinRE

And the new drive after installation looks like this:

adam>sudo fdisk -l /dev/sda
Disk /dev/sda: 894.25 GiB, 960197124096 bytes, 1875385008 sectors
Disk model:  SA400S37960G   
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 33553920 bytes
Disklabel type: dos
Disk identifier: 0x59d38595

Device     Boot     Start        End   Sectors   Size Id Type
/dev/sda1            2048     104447    102400    50M  7 HPFS/NTFS/exFAT
/dev/sda2          104448  936661644 936557197 446.6G  7 HPFS/NTFS/exFAT
/dev/sda3       936663040  937697279   1034240   505M 27 Hidden NTFS WinRE
/dev/sda4       937699326 1875384319 937684994 447.1G  f W95 Ext'd (LBA)
/dev/sda5  *    937699328  938747903   1048576   512M ef EFI (FAT-12/16/32)
/dev/sda6       938749952 1875384319 936634368 446.6G 83 Linux

The output of the Boot Repair operation which fixed the problem is attached.

boot_repair_pastebin_output.txt

I had discussed this issue on the forums here but I've summarized the relevant info in this report.

[adam4235]

I noticed #42 may be relevant. It mentions os-prober - could it be that os-prober didn't run during installation for some reason?
Edit: I don't think that can be it, because I had tried running sudo update-grub after installation and that didn't fix the problem, and apparently update-grub runs os-prober. Boot Repair is what fixed it.