In the Japanese manual on page 16 there is a memo next to the parameter Play: TargetTrack TRACK 1.
This says and I can confirm that when you press the "EXIT" button, the "Edit" pad button will flash green indicating that TRACK 1 is the current target track. Now if you press and hold the "EXIT" button while pressing any of the other TRACK 2-5 "Edit" buttons, you can change this target track from TRACK 1 to lets say TRACK 3 for example. THEN, if you have a Pedal assigned to REC, you can record a loop on that new current target track.
So let's say I have the Boss RC-505 setup to REC using Pedal Assign 1. I currently have my Target Track set for TRACK 1. I am playing the guitar and simply can record my first loop using my foot onto target track 1. Now is the difficult part. If I'm in the middle of my jam using both hands and want to record a second track, I can't do that. The reason is that I have to physically take my right hand away from the guitar and press hold EXIT while selecting EDIT for TRACK 2 to change the Target Track to TRACK 2. Then I can continue playing the guitar and record using the foot pedal.
At the moment, there is no way ( that I can find ) to control the changing of the Target Track using a foot pedal rather than my hand manually holding Exit and pressing Edit.
For synth players, vocalists, beat boxers, this may not be an issue. However, for two handed instruments like a guitar or bass, it might be tricky unless you factor in changing the target track by hand into your song.
Perhaps there is another way and maybe this isn't such a big issue, but I thought it was worth mentioning in case people want to use the RC-505 completely hands free. It may be difficult.
Hope this clarifies my original post a bit...laugh. Thanks!!