Garmin G4xx are not parsed

[AntonKukoba1]

gcdstruct output:

`Opening .\SW_INVNTRY.GCD
#000: TLV Type 0001 at 0x8, 1 Byte - Checksum rectifier
#1: TLV Type 0002 at 0xd, 21 Bytes - Padding
#2: TLV Type 0003 at 0x26, 9 Bytes - Part number?
#3: TLV Type 0005 at 0x33, 55 Bytes - Copyright notice
#4: TLV Type 0001 at 0x6e, 1 Byte - Checksum rectifier
#5: TLV Type 0002 at 0x73, 3977 Bytes - Padding
#6: TLV Type 0001 at 0x1000, 1 Byte - Checksum rectifier
#7: TLV Type 0006 at 0x1005, 10 Bytes - Block Type 7 format definition

• Field list: 000b 000a 100a 2015 5003
  Nuvi 205w SKU #8: TLV Type 0007 at 0x1013, 8 Bytes - Binary descriptor
• Field 1 (000b): Reset/Downgrade flag: 0x0001 / 1
• Field 2 (000a): XOR flag/value: 0x0000 / 0
• Field 3 (100a): Block type: 0x0401 / 1025
• Field 4 (2015): Binary length: 3043 Bytes
  Traceback (most recent call last):
  File ".\gcdstruct.py", line 28, in
  gcd.print_struct()
  File "D:\Work\other\Garmin\gcd-parser\grmn\gcd.py", line 90, in print_struct
  print("#{:03d}: {}".format(i, tlv))
  File "D:\Work\other\Garmin\gcd-parser\grmn\tlv.py", line 407, in str
  txt += "\n - Unknown header format (0x{:04x} / 0x{:04x})".format(hdr1, hdr2)
  NameError: name 'hdr1' is not defined`

GCD file is attached
SW_INVNTRY.zip