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@gmail.com