I can see this came across as an attack - it was not intended as such. This IS me engaging. This thread is where I first learned about this product, I've posted in here before, other people have posted support questions here, and it's where I returned to report my honest experiences trying to use it. I'm more than happy to work with you to help solve this, and that's in my best interests too. I prefer to engage with things like this publicly and transparently, and it can be great PR for you and your company to be seen publicly to be responsive and engaged in fixing problems as they occur.
As for frustration, the issue itself is only mildly frustrating, in fact I love troubleshooting issues like this and take it as a challenge. To be honest, I was more frustrated by the closed-source component in the firmware. ZuluIDE was clearly marketed as having open-source firmware, which I've found is only partially true. I would have been able to fix this myself and contribute back if it was fully open-source, and finding that wasn't possible surprised me, as it was part of my thinking when buying the ZuluIDE that "if I have problems with it, I can fix them", but then I hit this wall. I understand the issue of clones, and the worry about doing all the R&D only to be undercut by cheap copies on AliExpress. I get it. If you picked up frustration in my post though, it was more around this discovery than the issue itself. I bought this product with the intention to extend its functionality, as I mentioned before around the DOS program to switch disc images. Finding that the core part that drives the actual bus communication is walled off was unexpected.
Now you've sent me a DM. I'd prefer to engage more openly here in this thread or via GitHub. Since I've talked about this issue publicly, I think it'd be in your interest to have the support and resolution be public too. I'm on the train right now heading into work, and I won't have a chance to tinker with this more tonight, but tomorrow evening I'll open an issue on GitHub, and send through some sniffer logs and further info. I'm also happy to roll back to a prior firmware version if you can point to a particular older revision you suspect might be more likely to be problem free, such as one prior to the dual-device mode being introduced. If you can let me know a revision to try, I can probably squeeze that in quickly this evening, which might help rule a bunch of things out from the get-go.