get the Cosmo Communicator's latest OTA update from the DigitimeTech server

FetchCosmoUpdate.py

import binascii, struct, zlib
 
key = b'Ti92T_77Zij_MiTik'
 
def decrypt_pkt(buf):
    a = buf[:2]
    b = buf[10:12]
 
    if buf[8] == 1:
        raise 'gzipped!!'
    if buf[9] != 1:
        raise 'not encrypted!!'
 
    expected_crc = struct.unpack_from('<I', buf, 4)[0]
    assert(expected_crc == zlib.crc32(buf[8:]))
 
    expected_len = struct.unpack_from('<H', buf, 2)[0]
    assert(expected_len == (len(buf) - 12))
 
    payload = bytearray(buf[12:])
    for idx in range(len(payload)):
        key_idx = idx % len(key)
        payload[idx] ^= key[key_idx]
    return (a, b, bytes(payload))
 
def encrypt_pkt(a, b, buf):
    result = bytearray(len(buf) + 12)
    result[0] = a[0]
    result[1] = a[1]
    struct.pack_into('<H', result, 2, len(buf))
 
    result[8] = 0 #not gzipped
    result[9] = 1 #encrypted
    result[10] = b[0]
    result[11] = b[1]
    for i in range(len(buf)):
        result[12 + i] = buf[i] ^ key[i % len(key)]
 
    struct.pack_into('<I', result, 4, zlib.crc32(result[8:]))
    return bytes(result)


# phone_id may be any non-empty string
# if empty or missing, a new phone_id is generated and returned by the server
import json, requests
blob = dict(
    gen=dict(
        customer_id="EASTAEON",
        project_id="FTPRO16945",
        phone_id="",
        softver="Cosmo-9.0-Planet-10292019-V15.<20191029_1401>",
        count_succ=0,
    ),
)

raw_pkt = (b'3T', b'\x00\x01', json.dumps(blob, separators=(',',':')).encode('utf-8'))
# result = requests.post('http://47.254.145.86/v3/mob/chk', data=encrypt_pkt(*raw_pkt))
result = requests.post('https://app.fota.digitimetech.com/v3/mob/chk', data=encrypt_pkt(*raw_pkt), verify=False)
magic, flags, payload = decrypt_pkt(result.content)
print(json.loads(payload))