A script to remove all lfs files and commits of a repository.

rm-lfs.sh

#/bin/zsh

echo "converting lfs to normal git repo..."

if [ $# -eq 0 ]
  then
    echo "Use: rm-lfs.sh [http-git-url]"
    exit
fi

REPO=$1
REPODIR=`echo "$REPO" | rev | cut -d '/' -f 1 | rev`
FILESTXT="$REPODIR-lfs.txt"

# prepare
if [ -d "$REPODIR" ]; then rm -Rf "$REPODIR"; fi

# clone
git lfs uninstall
git clone "$REPO" "$REPODIR"

# list all files
cd "$REPODIR"
git lfs ls-files --all > "../$FILESTXT"

# create lfs file index
LSFFILES=()
while IFS= read -r line
do
	# caution, sometimes it's an asterix, sometimes a dash!
	# https://stackoverflow.com/a/36585611/1138326
	NORMLINE=`echo $line | sed 's/*/-/'`
	echo "$NORMLINE"
	LFSFILE=`echo "${NORMLINE#* - }"`
	LSFFILES+=( "$LFSFILE" )
done < "../$FILESTXT"

# remove git lfs
git rm .gitattributes

# run bfg cleaner for each file
LSFFILENAMES=()
for LFSFILE in "${LSFFILES[@]}"; do
	FILENAME=`echo "$LFSFILE" | rev | cut -d '/' -f 1 | rev`
	LSFFILENAMES+=( "$FILENAME" )
done

echo "removing all files with a single command"
LFSARGS="{"$(IFS=,; printf '%s' "${LSFFILENAMES[*]}")"}"
echo $LFSARGS
bfg --delete-files "$LFSARGS"

# reflog
git reflog expire --expire=now --all && git gc --prune=now --aggressive

# remove files from head and commit
for LFSFILE in "${LSFFILES[@]}"; do
	FILENAME=`echo "$LFSFILE" | rev | cut -d '/' -f 1 | rev`

	# completely removes file
	git rm -f "*$FILENAME"

	# removes file from lfs an adds them to normal git
	# git rm --cached "*$FILENAME"
	# git add "*$FILENAME"
done
git commit -m "removed lfs files from repository"

echo ""
echo ""
echo "FINISHED! now run 'git push --force' to upload it to the server!"
echo "After that install git lfs again: 'git lfs install'"
echo "And remove git lfs-index from repo: 'rm -rf .git/lfs'"

read -p "Press enter to push changes!"

git push --force

# remove chunk
rm -rf .git/lfs
git lfs install
exit

did you check that this script delete all the lfs from all the branches ?