Problems flashing the Octopus board, possibly

V-core-4 500mm. Desperately trying to move past the Octopus flash part of the installation but am continually getting an error that it can't connect to Klipper. Tried flashing via DMU and when I try from an SDcard it just errors again. Spent hours communicating with Ratrig and they have now suggested that somebody here might know because they seem to have run out of ideas.