Dual Boot : no grub display

[lsdmesg]

i have a dual boot laptop with windows 10 and ubuntu. Recently, the grub stopped showing on screen. Also even the HP logo at the start is not shown. The laptop boots into ubuntu(the preferred option in grub). The screen works fine and boot partition shows windows boot image also.

It seems that the grub is working fine behind. I used a grub customizer to default the windows boot  in grub and the screen stays blank and nothing happens.

I GUESS something is wrong with windows or BIOS.

[TheOldMan]

First - I do not have experience with dual boot and Linux grub, but if the system will start Ubuntu OK and it then functions OK, there is most likely not a problem with the BIOS, especially if you did not change any settings in the BIOS.

2) I am not quite sure what you mean by "It seems that the grub is working fine behind."

3) I would expect there is nothing wrong with the Windows install expect the boot loader got messed up by whatever you did with Grub.  Here is an article about fixing the Grub bootloader

https://www.howtogeek.com/114884/how-to-repair-grub2-when-ubuntu-wont-boot/

See if that helps.  You could explore this remedy, it works well with what you are attempting.

https://neosmart.net/EasyBCD/

Use the free version to fix the bootloader

[WAWood]

@lsdmesg 

I used Grub-Customizer all the time and it is, unfortunately, not very reliable.

I changed the partition arrangement on my Windows volume recently, ran Sudo update grub to detect that, and then reran Grub-customizer to change the menu.

But when I rebooted and select the Windows option from the menu, it did not boot.

Suspecting the worst, I disconnected the Linux drive and booted directly from the Windows drive -- and it booted fine, including ALL the three different OS versions I have.

So, I reconnected the Linux drive and had to rerun Grub-customer TWICE more before it properly updated the boot options.

All I can suggest is that you rerun it several times -- and in the meantime, look through the details of the grub config file to ensure they are correct.

You would need to check with a Linux forum about detail grub config file settings are those are quite complicated.