FixMacUpdates.sh

#!/usr/bin/env bash

###
 # FixMacUpdates.sh
 # A Script to Modify Updates for Installation on Unsupported Macs
 #
 # Copyright (c) 2020-2021 Dayo Akanji
 # MIT License
###



###
 # USAGE:
 # 1. Make the script executable in Terminal by typing: chmod +x '/path/to/FixMacUpdates.sh'
 #  - To get the path, drag the 'FixMacUpdates.sh' file into Terminal after typing: chmod +x
 # 2. Download and mount the Apple Update dmg file
 # 3. Drag the pkg file to your desktop from the dmg
 # 4. Drag the 'FixMacUpdates.sh' file into Terminal
 # 5. Leave a space after the command that appears and drag the pkg file into Terminal and press 'Enter'
 #  - You can press 'Enter' directly after 'FixMacUpdates.sh' if you first rename the pkg file as 'SecUpd.pkg'
###

# Provide custom colours in Terminal
msg_other() {
    echo -e "\033[0;36m$1\033[0m"
}
msg_info() {
    echo -e "\033[0;33m$1\033[0m"
}
msg_status() {
    echo -e "\033[0;32m$1\033[0m"
}
msg_error() {
    echo -e "\033[0;31m$1\033[0m"
}

## ERROR HANDLER ##
runErr() { # $1: message
    # Declare Local Variables
    local errMessage

    errMessage="${1:-Runtime Error ... Exiting}"
    echo ''
    msg_error "${errMessage}"
    echo ''
    echo ''
    exit 1
}
trap runErr ERR

DESKTOP_DIR="${HOME}/Desktop"
EXPANDED_DIR="${DESKTOP_DIR}/ExpandedUpdate"
DISTIBUTION_FILE="${EXPANDED_DIR}/Distribution"
OLD_UPDATE_PKG="${1:-${DESKTOP_DIR}/SecUpd.pkg}"
NEW_UPDATE_PKG="${DESKTOP_DIR}/ModifiedUpdate.pkg"

# Clear Prompt
clear

# Commence Procedure
msg_info '###--------------------->>'
msg_info ' ### Mac Update Modifier >>'
msg_info '  ###--------------------->>'

if [ ! -f "${OLD_UPDATE_PKG}" ] ; then
    # Terminate Procedure
    echo ''
    msg_error '  Could not find update pkg ... Exiting'
    echo ''
else
    # Progress Procedure
    msg_other '  Preambles'
    echo -ne 'Please Wait...\r'
    rm -fr "${EXPANDED_DIR}"
    rm -fr "${NEW_UPDATE_PKG}"
    sleep 2
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Expand Package'
    echo -ne 'Please Wait...\r'
    sleep 2
    echo -ne '                                                                        \r'
    echo -ne 'This may take a while...\r'
    pkgutil --expand "${OLD_UPDATE_PKG}" "${EXPANDED_DIR}"
    echo -ne '                                                                        \r'
    echo -ne 'Please Wait...                                                          \r'
    sleep 4
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Disable Volume Check'
    echo -ne 'Please Wait...\r'
    perl -i -p -e 's#VolumeCheck\(prefix\) \{#VolumeCheck(prefix) {return true;#g' "${DISTIBUTION_FILE}"
    sleep 2
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Disable Installation Check'
    echo -ne 'Please Wait...\r'
    perl -i -p -e 's#InstallationCheck\(prefix\) \{#InstallationCheck(prefix) {return true;#g' "${DISTIBUTION_FILE}"
    sleep 2
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Create Modified Update Package'
    echo -ne 'Please Wait...\r'
    sleep 4
    echo -ne '                                                                        \r'
    echo -ne 'This takes some time...\r'
    pkgutil --flatten "${EXPANDED_DIR}" "${NEW_UPDATE_PKG}"
    echo -ne '                                                                        \r'
    echo -ne 'Please Wait...                                                          \r'
    sleep 2
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Cleaning Up'
    echo -ne 'Please Wait...\r'
    rm -fr "${EXPANDED_DIR}"
    rm -fr "${OLD_UPDATE_PKG}"
    sleep 2
    echo -ne '                                                                        \r'
    msg_status '  ...OK                                                                 '

    msg_other '  Notify'
    msg_status "  ${NEW_UPDATE_PKG} is ready for installation"
fi

# Conclude Procedure
msg_info '  ###--------------------->>'
msg_info ' ### Mac Update Modifier >>'
msg_info '###--------------------->>'
echo ''
echo ''