Nord Drum 2 checksum

[sockmonkey]

Hi, I've been developing a patch editor/generator for the ND2, but am hung up on a system exclusive issue. Does anyone here know how the checksums are calculated for the Nord Drum 2? There's a 7-bit (1 byte) checksum for requests and a 21-bit (3 byte) checksum for voice data. I've tried a variety of CRC algorithms without hitting on the right one, maybe someone here knows the secret sauce.

Thanks, Jeremy

[Happy]

Wanted to do the same and asked Nord for this 2-3 years ago for the D2 and D1 to save patches more easily. Spend days on trying to figure it out but had to give up. Nord's answer then was that sysex/checksum "was not a secret but they just did not have it and CC could do the job". It is a kind if interesting as for older products (NL1/2/3) the Sysex was made available but then suddenly not anymore for any products. Around the same time Roland started to stop disclosing Sysex as well. Really like the D1 & D2, except for this. It is the main reason why I did not buy an NL4, A1 and an Electro and went for Dave Smith / Sequential products.