System partition resize script for Nexus 5.

hh_repart

#!/sbin/sh
#
# Copyright (C) 2018 Unlegacy Android Project
# Copyright (C) 2018 Svyatoslav Ryhel
# Copyright (C) 2019 Nick80835
# Copyright (C) 2019 z3dd3r
#
# Made for Hammerhead
#


#
# Function will print usage instruction
#
print_usage_instruction()
{
echo " ";
echo "Dump info about partitions to /sdcard/partitions.log :";
echo "hh_repart -d";
echo " ";
echo "Modify size of partitions :";
echo "hh_repart -m";
echo " ";
echo "Restore size of partitions :";
echo "hh_repart -r";
echo " ";

return 0
}


#
# Function will dump info about current partitions to /sdcard/partitions.log
#
dump_partitions_size()
{
echo "Dumping info about partitions...";
parted /dev/block/mmcblk0 unit b p quit -> /sdcard/partition.log

echo "-- Finished --";
return 0
}


#
# Function will check current partitions
# Returns 3 values:
#    0 - Original partitions layout with 1.0Gb system
#    1 - Modified partitions layout with 1.5Gb system
#  255 - Unknown partitions layout. Modification SHOULD NOT be performed!
#
check_partitions_size() 
{
echo "Checking size of partitions...";
parted /dev/block/mmcblk0 unit b p quit -> /tmp/part

if grep "1073741824B" /tmp/part > /dev/null
then
  echo "-- Original partitions --";
  rm /tmp/part
  return 0
elif grep "1536000512B" /tmp/part > /dev/null
then
  echo "-- Modified partitions --";
  rm /tmp/part
  return 1
else
  echo "-- Unknown partitions --";
  rm /tmp/part
  return 255
fi
}


#
# Function will modify size of partitions
# /system partition will be increased to ~1444MB
# /cache partition will be decreased to ~255MB
# 
modify_partitions_size()
{
echo "Modifying partitions...";

mkdir /tmp/backup
dd if=/dev/block/mmcblk0p26 of=/tmp/backup/crypto.img

umount /data
umount /system
umount /cache

parted /dev/block/mmcblk0 <<EOF
  rm 25
  rm 26
  rm 27
  mkpart primary 192937984B 1728938495B
  name 25 system
  mkpart extended 1728938496B 1760395775B
  name 26 crypto
  mkpart primary 1760395776B 2032140287B
  name 27 cache
  quit
EOF

sleep 1

make_ext4fs /dev/block/mmcblk0p25
make_ext4fs /dev/block/mmcblk0p27

e2fsck -p -f /dev/block/mmcblk0p25
e2fsck -p -f /dev/block/mmcblk0p27

dd if=/tmp/backup/crypto.img of=/dev/block/mmcblk0p26
rm /tmp/backup/crypto.img

echo "-- Finished --";
reboot recovery
return 0;
}


#
# Function will restore size of partitions to stock setup
# 
restore_partitions_size()
{
echo "Restoring partitions...";

mkdir /tmp/backup
dd if=/dev/block/mmcblk0p26 of=/tmp/backup/crypto.img

umount /data
umount /system
umount /cache

parted /dev/block/mmcblk0 <<EOF
  rm 25
  rm 26
  rm 27
  mkpart primary 192937984B 1266679807B
  name 25 system
  mkpart extended 1266679808B 1298137087B
  name 26 crypto
  mkpart primary 1298137088B 2032140287B
  name 27 cache
  quit
EOF

sleep 1

make_ext4fs /dev/block/mmcblk0p25
make_ext4fs /dev/block/mmcblk0p27

e2fsck -p -f /dev/block/mmcblk0p25
e2fsck -p -f /dev/block/mmcblk0p27

dd if=/tmp/backup/crypto.img of=/dev/block/mmcblk0p26
rm /tmp/backup/crypto.img

echo "-- Finished --";
reboot recovery
return 0;
}

if [ -z "$1" ]; then
  print_usage_instruction
  exit 0
fi

if [ "$1" == "-d" ]; then
  dump_partitions_size
  exit 0
fi

if [ "$1" == "-m" ]; then
  check_partitions_size
  if [ $? -eq 0 ]; then
    modify_partitions_size
  fi
  exit 0
fi

if [ "$1" == "-r" ]; then
  check_partitions_size
  if [ $? -eq 1 ]; then
    restore_partitions_size
  fi
  exit 0
fi

exit 0

Origin:
https://sourceforge.net/projects/nexus5oof/files/TWRP/

Usage:

# update partition
hh_repart -m

# restore partition
hh_repart -r

Reference:

1. https://forum.xda-developers.com/google-nexus-5/orig-development/rom-lineageos-16-0-nexus-5-t3921162
2. https://forum.xda-developers.com/showpost.php?p=79928889&postcount=190

Thank you for this! Saved my butt when I was trying to flash the latest Lineage onto a rescued Nexus 5.