Windows replaced Ubuntu's GRUB

I am using Ubuntu with windows 11 as dual boot but due to faulty update from Microsoft, I have to reinstall windows 11. Now, windows 11 replaced Ubuntu's GRUB.

How to recover grub?

I have an SSD with two partitions — one for windows and the other for Ubuntu.

First, check with your PC-Motherboard/Laptop Manufacturer to know about the hotkey to press on start up to enter into Boot options, before your Windows11 is booted. There you will see option to Boot from Operating Systems you installed in your storage drives, select Ubuntu from it.

After booting into your Ubuntu, open your Terminal application then run:

sudo update-grub

This will update your Grub and rewrite your EFI partition.