# Make root file system writable:
mount -o remount,rw /dev/ubi0 /

# Install feature rich busybox
curl --insecure https://busybox.net/downloads/binaries/1.31.0-defconfig-multiarch-musl/busybox-armv7l > /bin/busybox-v1.31.0-armv7l
chmod +x /bin/busybox-v1.31.0-armv7l
cd /bin
ln -s busybox-v1.31.0-armv7l sysctl

# Create sysctl.conf with modified parameters
cat <<EOF > /etc/sysctl.conf
net.ipv4.ip_local_port_range=15000 64000
net.ipv4.tcp_fin_timeout=30
net.ipv4.tcp_tw_recycle=1
net.ipv4.tcp_tw_reuse=1
net.core.somaxconn=1024
net.netfilter.nf_conntrack_max=30000
EOF

# Apply parameters
sysctl -p

# Create script to apply parameters on startup
cat <<'EOF' > /etc/init.d/increaselimits.sh
#!/bin/sh

case "$1" in
        start)
                echo "Increasing Connection Limits..."
                sysctl -p
                exit 0
                ;;
        stop)
                echo "Not implemented..."
                exit 1
                ;;
        *)
                echo "$0: unrecognized option $1"
                exit 1
                ;;
esac

EOF

# Make script executable and create link in /etc/rc3.d
chmod 755 /etc/init.d/increaselimits.sh
cd /etc/rc3.d
ln -s ../init.d/increaselimits.sh S99increaselimits

# Make root filesystem read only
mount -o remount,ro /dev/ubi0 /