diff --git a/install-setvars.sh b/install-setvars.sh
new file mode 100755
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--- /dev/null
+++ b/install-setvars.sh
@@ -0,0 +1,178 @@
+#!/bin/bash
+
+### begin function definitions ###
+
+# Check that we can access the directory that ocntains this script, as well
+# as the root directory of the installer USB. Access to both of these
+# directories is vital, and Catalina's TCC controls for Terminal are
+# capable of blocking both. Therefore we must check access to both
+# directories before proceeding.
+checkDirAccess() {
+    # List the two directories, but direct both stdout and stderr to
+    # /dev/null. We are only interested in the return code.
+    ls "$VOLUME" . &> /dev/null
+}
+
+### end function definitions ###
+
+# Make sure there isn't already an "EFI" volume mounted.
+if [ -d "/Volumes/EFI" ]
+then
+    echo 'An "EFI" volume is already mounted. Please unmount it then try again.'
+    echo "If you don't know what this means, then restart your Mac and try again."
+    echo
+    echo "install-setvars cannot continue."
+    exit 1
+fi
+
+# For this script, root permissions are vital.
+[ $UID = 0 ] || exec sudo "$0" "$@"
+
+if [ "x$1" = "x-v" -o "x$1" = "x--verbose" ]
+then
+    VERBOSEBOOT="YES"
+    echo 'Verbose boot option enabled.'
+    shift
+fi
+
+# Allow the user to drag-and-drop the USB stick in Terminal, to specify the
+# path to the USB stick in question. (Otherwise it will try hardcoded paths
+# for a presumed Big Sur Golden Master/public release, beta 2-or-later,
+# and beta 1, in that order.)
+if [ -z "$1" ]
+then
+    for x in "Install macOS Big Sur" "Install macOS Big Sur Beta" "Install macOS Beta"
+    do
+        if [ -d "/Volumes/$x/$x.app" ]
+        then
+            VOLUME="/Volumes/$x"
+            APPPATH="$VOLUME/$x.app"
+            break
+        fi
+    done
+
+    if [ ! -d "$APPPATH" ]
+    then
+        echo "Failed to locate Big Sur recovery USB stick."
+        echo Remember to create it using createinstallmedia, and do not rename it.
+        echo "If all else fails, try specifying the path to the USB stick"
+        echo "as a command line parameter to this script."
+        echo
+        echo "install-setvars cannot continue and will now exit."
+        exit 1
+    fi
+else
+    VOLUME="$1"
+    # The use of `echo` here is to force globbing.
+    APPPATH=`echo -n "$VOLUME"/Install\ macOS*.app`
+    if [ ! -d "$APPPATH" ]
+    then
+        echo "Failed to locate Big Sur recovery USB stick for patching."
+        echo "Make sure you specified the correct volume. You may also try"
+        echo "not specifying a volume and allowing the patcher to find"
+        echo "the volume itself."
+        echo
+        echo "install-setvars cannot continue and will now exit."
+        exit 1
+    fi
+fi
+
+# Check if the payloads directory is inside the current directory. If not,
+# it's probably inside the same directory as this script, so find that
+# directory.
+if [ ! -d payloads ]
+then
+    BASEDIR="`echo $0|sed -E 's@/[^/]*$@@'`"
+    [ -z "$BASEDIR" ] || cd "$BASEDIR"
+fi
+
+# Check again in case we changed directory after the first check
+if [ ! -d payloads ]
+then
+    echo '"payloads" folder was not found.'
+    echo
+    echo "install-setvars cannot continue and will now exit."
+    exit 1
+fi
+
+# Check to make sure we can access both our own directory and the root
+# directory of the USB stick. Terminal's TCC permissions in Catalina can
+# prevent access to either of those two directories. However, only do this
+# check on Catalina or higher. (I can add an "else" block later to handle
+# Mojave and earlier, but Catalina is responsible for every single bug
+# report I've received due to this script lacking necessary read permissions.)
+if [ `uname -r | sed -e 's@\..*@@'` -ge 19 ]
+then
+    echo 'Checking read access to necessary directories...'
+    if ! checkDirAccess
+    then
+        echo 'Access check failed.'
+        tccutil reset All com.apple.Terminal
+        echo 'Retrying access check...'
+        if ! checkDirAccess
+        then
+            echo
+            echo 'Access check failed again. Giving up.'
+            echo 'Next time, please give Terminal permission to access removable drives,'
+            echo 'as well as the location where this patcher is stored (for example, Downloads).'
+            exit 1
+        else
+            echo 'Access check succeeded on second attempt.'
+            echo
+        fi
+    else
+        echo 'Access check succeeded.'
+        echo
+    fi
+fi
+
+MOUNTEDPARTITION=`mount | fgrep "$VOLUME" | awk '{print $1}'`
+if [ -z "$MOUNTEDPARTITION" ]
+then
+    echo Failed to find the partition that
+    echo
+    echo is mounted from. install-setvars cannot proceed.
+    exit 1
+fi
+
+DEVICE=`echo -n $MOUNTEDPARTITION | sed -e 's/s[0-9]*$//'`
+PARTITION=`echo -n $MOUNTEDPARTITION | sed -e 's/^.*disk[0-9]*s//'`
+echo $DEVICE $PARTITION
+
+if [ "x$PARTITION" = "x1" ]
+then
+    echo "The volume $VOLUME"
+    echo "appears to be on partition 1 of the USB stick, therefore the stick is"
+    echo "incorrectly partitioned (possibly MBR instead of GPT?)."
+    echo "Please refer to the micropatcher README or other documentation for more"
+    echo "information."
+    echo
+    echo "install-setvars cannot continue."
+fi
+
+diskutil mount ${DEVICE}s1
+if [ ! -d "/Volumes/EFI" ]
+then
+    echo "Partition 1 of the USB stick does not appear to be an EFI partition, or"
+    echo "mounting of the partition somehow failed."
+    echo "Please refer to the micropatcher README or other documentation for more"
+    echo "information."
+    echo
+    echo "install-setvars cannot continue."
+fi
+
+if [ "x$VERBOSEBOOT" = "xYES" ]
+then
+    cp -r setvars/EFI-verboseboot /Volumes/EFI/EFI
+else
+    cp -r setvars/EFI /Volumes/EFI/EFI
+fi
+
+umount /Volumes/EFI || diskutil unmount /Volumes/EFI
+
+echo
+echo 'Syncing.'
+sync
+
+echo
+echo 'install-setvars finished.'