I have the same issue with my Dynavin N6: I loose audio every few months. Disconnecting and reconnecting the battery always fixes it. I and Jeff have gone through troubleshooting steps with no success. I got a new IBUS decoder but that did not fix it. Reconnecting the Dynavin or decoder does not help. Whenever audio is lost, I always find the IBUS decoder with a red light on it. INPA/DIS/SSS show that the DSP amp is fine. Jeff thinks that there's something wrong with the DSP amp. But I never had such issues with the factory headunit. Anyhow, I can live with the issue as it happens every 2-3 or so months, although reaching the battery is a hustle if you have to do it every so often.

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'05 E53 X5 4.4i, '97 E39 528, '07 E92 335i, '16 F86 X6M.