I would like to restore root-filesystem among others to smaller disk or disksystem.

My setup currently:
sda1 = /boot
sda2 = swap
sda3 = /

First I took backup with dd of 63 first sectors and restored it to smaller disk.

Then I took dumps with sfdisk of partition table and restored it to smaller disk. Because physical disk is smaller, it doesn't work.

After that I restored partitions of only sda1 and sda2 with sfdisk and made smaller than original sda3 with cfdisk.

Then restored filesystem with fsarchiver. System can't find operating system. After that I tried to install grub with:

"grub-install /dev/sda"

but it failed with error:
/dev/sda: Not found or not a block device.

After I did
"mount /dev/sda1 /something/somewhere"
and

grub-install --root-directory=/something/somewhere
... I managed to install grub.

However, now I can see only grub-commandline when booting, not grub menu.

How should I install grub so that menu would also work and I would be able to boot?