Mine came working at 115200, but I udpated to the newer firmware just now and it seems OK
However one thing that went very wrong was the CPUpdate command, it ended up spitting out reems of jibberish characters and the only way to reset it seemed to be to upload the firmware again
I have installed a VM with Lununtu preconfigued with the toolchain and SDK, but I'm not entirely sure where to start writing my own firmware, as information is thin on the ground.
If I understand it correctly, It seems that its possible to upload the system software separately from the application software.
The builds that I did in the VM using the SDK example, seems to generate 2 files, both of which, (I think) need to be uploaded.
However I've not got as far as that yet