Seems to be some sort of software issue. I'm unable to code DSP per these instructions using IBUS-App:
https://support.avinusa.com/hc/en-us...l-Update-Guide
INPA/DIS/Bimmercode can talk to the DSP, turn it on, etc. No error codes stored. When turning on DSP using these apps, the hissing sound goes away.
Is everyone else able to code their DSP using the IBUS-App? Are you able to read data off it using IBUS-App?