Cannot get GRUB screen after reinstalling Windows 10.
 

Hi.

I am having problem getting the Grub screen to display during Linux Ubuntu distro launch.
Been using Ubuntu for 3 months with no problems.
Have Ubunti Distro installed on my Flash Drive.

Description: Ubuntu 18.04.1 LTS
Release: 18.04
Codename: bionic
$ uname -r 4.15.0-29-generic.

Had to reinstall (Windows 10) 2 days ago after suspecting my computer was infected by malware.
Wiped my C:\ drive and just reinstalled win10. All my apps/data have since been restored/applied.


To launch Linux, from windows, Hit F12 (restart) having Ubuntu flash drive in usb port.

Screen Shows:
Boot Mode is set to UEFI secured boot off
Legacy Boot:
Minicard ssd
USB storage device

UEFI Boot:
Ubuntu
Windows Boot Manager
Other Option:

Selected USB Storage option: Receive message: Invalid Partition Table!
Tried Ubuntu option: Receive Message: F1 to retry, F2 to boot into setup, F5 onboard diagnostic.
Tried both options again having Legacy with secured boot off. Same results.

Installed Boot-Repair-Disk. Message returned Boot Successfully Repaired (see attachment of Boot repair results). After repair, tried USB storage and Ubuntu options. Same error results as above.

The only change I did when reinstalling Windows 10 is use the file path name different from the previous win10.

I have a old system-image backup, but the Linux FD was built after the Macrium backup,

Is there anything else I can try short of reinstalling the Ubuntu Linux Distro again?.

Thanks.
TC.

Windows 10 should have a 'Custom' install option which you can select and then install to the partitions you want. Apparently, you did not use or see that option and you have overwritten your Ubuntu install. No sign of Ubuntu in your boot info output other than the entry in efibootmgr. No Ubuntu files on the EFI partition either.

So if I understand correctly, you can not now launch the Ubuntu usb, correct? Is this the same usb you used to install it previously? Have you tried using a different usb port? Have you tested the usb on another computer?

@yancek.
I decided to do a clean Win10 install due to the possible malware infected on my computer.
I do not remember seeing custom install.
This is the same USB stick I installed Ubuntu 3 months ago. Currently I am away from my residence for 6 months. I will go to an internet shop and try launching Ubuntu.

One Question I have:
If I create a quick light version of Ubuntu on a FD stick.
Boot into Live environment with new flash drive. Begin the Installation.
Put the old Ubuntu FD stick in a different USB port.

Is there a way where I could substitute the new FD stick for the old, request a reinstall having documents be retained?

TC

When I installed windows 10, the option to do a regular/normal install or a Custom install which was right after the step requiring acceptance of the EULA.

I don't know what an "FD stick" is but it appears you are asking if you can begin the install with one device and then change to another. No, that won't work. You can do the install with one device then copy personal data from another device to the new install.