[chirp_devel] KG-UV9D Checksum

[dropkick23 at gmail.com]

I have been looking at Wouxun KG-UV9D trying to determine the record
checksum calculation.


I have tried a couple of CRC-8 online calculators without success.


I also used https://github.com/sitsec/bruteforce-crc on 223 memory records
hoping to find one polynomial that worked for all records, best was 30 of
223.


Examples:

read request record sent to radio all have checksum of 0x38:

7D 84 FF 03 58 58 38 38

7D 84 FF 03 5C 5C 3C 38

7D 84 FF 03 10 50 30 38

7D 84 FF 03 11 51 31 38

7D 84 FF 03 14 54 34 38

7D 84 FF 03 15 55 35 38



Memory records last byte is checksum:

7D 84 00 62 58 18 E7 18 E7 18 E7 18 E7 18 E7 18 E7 18 E7 1A E5 1A E5 1A E5
1A E5 1A E5 1A E5 1A E5 1A E5 18 E7 18 E7 18 E7 18 E7 18 E7 18 E7 18 E7 18
E7 1A E5 1A E5 1A E5 1A E5 1A E5 1A E5 1A E5 1A E5 18 E7 18 18 18 18 18 18
18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18 18
18 18 10


7D 84 00 62 58 D8 27 D8 27 D8 27 D8 27 D8 27 D8 27 D8 27 DA 25 DA DA 22 2A
32 32 CA C2 DA DA DA DA DA 39 E9 15 EA EA 12 1A 02 02 FA F2 EA EA EA EA EA
09 D9 25 DA DA 22 2A 32 32 CA C2 DA DA DA DA DA 39 E9 15 EA EA EA EA EA EA
EA EA EA BD D8 B9 CD A5 C0 B2 83 D4 B1 D0 A4 CC A9 DB E9 BE DB BA CE A6 C3
B1 83 8E


7D 84 00 62 58 98 98 60 68 70 70 88 80 98 98 98 98 98 7B AB 57 A8 A8 50 58
40 40 B8 B0 A8 A8 A8 A8 A8 4B 9B 67 98 98 60 68 70 70 88 80 98 98 98 98 98
7B AB 57 A8 A8 50 58 40 40 B8 B0 A8 A8 A8 A8 A8 4B 9B 67 98 CF AA CB BF D7
B2 C0 F4 A3 C6 A7 D3 BB DE AC 99 CE AB CA BE D6 B3 C1 F7 A0 C5 A4 D0 B8 DD
AF 98 96


If the checksum calculation can be determined, I believe it will also apply
to other Newer Wouxun radios KG-UV8D Plus is one example. It has a
different checksum calculation than the KG-UV8D with is a simple (sum mod
0xff)


I have been looking at this on and off for a few months now and feel I have
reached a dead end on the checksum calculation. Any help would be welcomed.


Fred

dropkick23 at gmail.com
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