Tascam released firmware 1.20 last week. It enables timecode, clearing up the mystery reports I got (see above) from loading files into iZotope Rx, no longer get error messages but haven't tried any timecode systems. They claim: "Support has been added for wireless timecode synchronized recording with Atomos Pty Ltd’s AtomX SYNC, UltraSync BLUE and other compatible products such as ATOMOS CONNECT and SHOGUN CONNECT. Video and audio files recorded with timecode data on multiple devices using synchronized recording can be aligned easily on editing software."
The hum lines (now at 36.5 kHz and 73 kHz) are almost gone on the left channel internal mics but still present on the right, will test with external mics later.
Jeff