Usb2din works, usb2usb doesn’t

[Raphie]

I’m trying to get midiOX to recognize my synth I/O for fw updates and sysex dumps.
When I patch PC USB (green, port 1 of 12 called MRCC) to any of the din outputs AND patch the corresponding DIN input to PC USB (blue, hold, choose port 1 of 12 called MRCC) this works. 
But when I do the same for PC USB from/to 1 of the 4 USB device ports it doesn’t? 
I’ve tried all virtual ports (1-4) of these as well. Any idea where I’m going wrong?

[oldgearguy]

It's a known issue. There's a couple threads about it somewhere on the forum. Same with DIN ports 7-12 (unless I missed an update)

[Jesse Johannesen]

I was at the Lab earlier this week and Steve was looking at MRCC Sysex code. I know there was some progress with making larger Sysex pass where they used to fail, but he's still looking for the bug on this part of the issue. More info as it becomes available.