File nexus7-fw-install of Package nexus7-fw-installer

#!/bin/sh

TMP_PATH="/tmp/nexus7_fw_install"
URL="https://dl.google.com/dl/android/aosp"
TGZ_FILE="broadcom-grouper-jzo54k-26240daf.tgz"
MD5_SUM="d9f54118d7dc467bea232e20017290a8"
SHA1_SUM="3eb767b236862a184fd1363066a58b1c792e9b19"
SELF_EXTRACTOR="extract-broadcom-grouper.sh"

mkdir -p $TMP_PATH
cd $TMP_PATH

if [ ! -e $TGZ_FILE ];
then
    echo "Downloading firmware package from: $URL/$TGZ_FILE"
    curl -k -o $TGZ_FILE $URL/$TGZ_FILE ;
fi

echo "$MD5_SUM  $TGZ_FILE" > $TGZ_FILE.md5
echo "$SHA1_SUM  $TGZ_FILE" > $TGZ_FILE.sha1

echo -e "\nChecking MD5 sum."
md5sum -c $TGZ_FILE.md5
if [ $? -eq 0 ];
then
    echo "MD5 sum verified." ;
else
    echo "MD5 checksum invalid."
    echo "Stopping further execution."
    exit 1 ;
fi

echo -e "\nChecking SHA1 sum."
sha1sum -c $TGZ_FILE.sha1
if [ $? -eq 0 ];
then
    echo "SHA1 sum verified." ;
else
    echo "SHA1 checksum invalid."
    echo "Stopping further execution."
    exit 2 ;
fi

if [ ! -e $SELF_EXTRACTOR ];
then
    echo -e "\nExtracting firmware package..."
    tar xf $TGZ_FILE ;
fi

if [ ! -d "vendor" ] ;
then
    echo -e "\nRunning self extractor..."
    echo "Please follow the instrutions and read the license."
    echo "Press <ENTER> to scroll down a single line."
    echo "Press <SPACE> to scroll down an entire page."
    ./$SELF_EXTRACTOR ;
fi

if [ $? -ne 0 ] ;
then
    echo -e "\nRunning the selfextractor terminated with non zero status."
    echo "Reasons could be that you didn't accept the license or an error happened."
    echo "Terminating this script."
    exit 3 ;
fi

if [ ! -d "vendor" ] ;
then
    echo -e "\nExtracted files not found."
    echo "Terminating the installation script."
    exit 4 ;
fi

mkdir -p /lib/nexus7_fw
cp -r vendor /lib/nexus7_fw

echo -e "\nInstallation of Nexus 7 firmware finished. :)"