xubuntu - How to repair /boot on LUKS encrypted harddrive?

i have laptop xubuntu installed.

at install chose full disk encryption option.

but yesterday accidentally dd-ed dsl image sda1 (/boot partition) instead sdb1 (pendrive).

how can repair /boot ?

hello tested following commands in laptop - yeah deleted in /dev/sda1 , got working again - here is:

get live-image , boot it.
first lets clean /dev/sda1 - open gparted; reformat /dev/sda1 ext2 , don't forget set "boot"-flag (right click on partition , select appropriate option) , confirm changes.
now prepare chroot installed system , switch it: sudo cryptsetup luksopen /dev/sda5 sda5_crypt sudo vgscan --mknodes sudo vgchange -ay sudo mount /dev/mapper/ubuntu--vg-root /mnt sudo mount /dev/sda1 /mnt/boot in /dev /dev/pts /proc /sys /run; sudo mount -b $i /mnt$i; done sudo chroot /mnt
okay let's delete , reinstall grub: apt purge grub-common (have terminal in fullscreen-mode due ncurses), might ask if shall delete - select yes; lets reinstall apt install grub-pc here select /dev/sda when asked.
lastly need reinstall kernel needed initrd*- , vmlinuz*-images /boot/ . installed kernels apt list --installed linux-image-* , reinstall kernel apt install linux-image-[version-numbers]-generic --reinstall - don't forget exchange brackets actual version number.
almost done; exit chroot ctrl-d , reboot!

used resources:

Primitatvve