Hi Brian,
I’ve been using the 6 track recorder heavily recently to record the stems of a complete session (because I’m using the ER301 as a mixer amongst other things) & it is fantastic!!
As is always the way Im now wishing I had a couple more extra tracks in the recorder - is it a possibility in a future firmware to increase the number of tracks that can be recorded simultaneously to say a maximum of 10 tracks or is there an architectural/system or performance limitation?
I just wanted to bump this, as I also was wondering if there is anything limiting this. I have really been enjoying how easy it is to multitrack jams (post-fade!) within the er-301, but when using stereo modules the 6 tracks can be somewhat limiting 
In the meantime you can record more tracks with Loopers. Just set it to have a really long buffer.
Can these looper buffers be written directly to the card?
My desire to have a 10 track recorder hasn’t gone away & would be a huge benefit for both studio & live work.
After recording to them you can save them to a card, yes. Just go into admin and buffer pool and you can save any buffers you have. I’m not sure if you can record a linked stereo pair in a looper though.
Thanks, unfortunately due to my patch already using pretty much the entire memory for other sample back I don’t think I can have several hours of additional stereo loopers
That makes sense. Having more tracks would be nice. Most of the time I lose focus or interest in a patch before I reach the limits. BTW the video you did with mylar melodies is what led me to get an ER-301. Love your music, and I can start seeing why you needed two ER-301s.
Also the 1u modules you use to do drum fills inspired me to prototype a 1u switch that can switch between two inputs, in my case drum gates, and mute them.
Many thanks!! Glad it gave you some ideas! 
It won’t work on all SD cards but here you go: