Restoring the Manjaro bootloader after unwanted removal

I have a nice compact Lenovo ThinkCentre that dual boots Manjaro Linux and Windows.
A couple of months back I let Windows update the firmware, and it wiped my Linux bootloader. The Linux system was still there and in good order, but I could access it only by first using my Manjaro installation USB stick, then finding the local EFI boot loaders, then selecting the Manjaro EFI loader.

I checked a bunch of pages that explained how to install the Manjaro GRUB, but all seemed risky, and more involved than seemed warranted.

Then I checked this page: Confused about re-installation of grub bootloader.

I’ll reproduce the best answer:

the chroot wiki bit assumes you’ve got a unbootable system and are looking for a rescue, hence you’re reinstalling grub.

You can do so from your terminal at any time, which will install the current grub package:

sudo grub-install

followed by:

sudo grub-mkconfig

To add context: before running those commands, I had booted using the USB stick and used that to locate my Manjaro EFI loader, and then load my system. I executed those two commands from a terminal in my Manjaro system, not in the system on the USB stick.