I'm digging my new P-121, but I play split bass almost all the time, and I'm wondering if anyone has a workaround to shut off the damper/sustain for that bass voice? The manual mentions nothing about it, or I missed it. I'd love to keep using sustain on the right hand, and have more freedom in the left. anyone?

Page 15 in your manual... Default is no damper when bass is selected in split mode... If you select sostenuto the sustain will work on left and right.

Saw that. It refers to the pedal UNIT. That's the three pedal attachment that's proprietary. So far, with a single damper, there's no way. Seems weird. Yamaha doesn't even sustain the strings.

UPDATE:
I spoke with Yamaha about this anomaly, and they are as baffled as I am. I opened a case, and they are looking into it. I also ordered the pedal unit that is "supposed" to give the feature I need, but I'll have to modify the structure, because I'm not using the home furniture stand. I need to make this road-worthy if I am going to keep using it. I like everything about it except this damper/sustain issue.
WISH LIST:
Make the layered strings sustain, and make the split bass IGNORE sustain.
Now, we wait.

Second UPDATE;
http://www.synthzone.com/forum/ubbthreads.php/topics/474894#Post474894

(the 3 ped unit works as stated)

Dave, does the Yamaha have a midi channel assigned to each part ?

Left side, right side parts. Just about every midi instrument does.

Then you should be able to defeat cc64 (hold) for the channel that uses bass.

I could not find a midi chart for the piano.

I found the reference manual for midi.. you should be able to turn off cc64 for left.

https://usa.yamaha.com/files/download/other_assets/2/1209032/p125_p121_en_mr_a0.pdf

Fran (et al ...)
All good, in theory, but nothing suggests that you can do a local CC ignore for a specific channel. The internal guts are capable of so much more than the organic controls allow. I tried splitting the midi channels, but - no result.

Dave call Yamaha and maybe they will give you the system exclusive HEX script to turn off the hold pedal on the split left.

Send the system script via micro edit from the PA4x sequencer... or your DAW. It should change and be locked, so make sure you also get the script to turn it back on.

This type of system exclusive is available on Roland gear.. I am sure they can give you the data.

If you examine the midi reference info.. it may be found.

I'm tired just reading all those steps, and still not sure it'll work. I'll modify the 3 pedal unit.

My head just Exploded reading this

A very simple procedure, if your gear is equipped to do it..

It's a hardware limitation. The guts can do what I want with the optional 3 pedal unit. It's the dedicated sustain pedal jack that's missing the "oooomph" factor.
That's got to be an oversight. Yamaha techs say that it should operate the way the 3 ped does.