I have had my TF for about a week now and am getting into it nicely. I do know the looper is only supposed to work in play mode, BUT I connected a TC 3 button G-switch via the aux socket and now I can get the looper to work in bank mode, but with a minor problem.
First you have to configure the aux TRS connections to Rec Play and Stop then save Preset 1:2 for example as the looper with your preferred settings. Now you can have a delay on preset 1:1 and switch to the looper in bank 1:2 whereupon the G-Switch does the necessary rec-play-stop functions.
Only problem is there is a slight delay in the start of the playback. It seems to be playing it correctly but the audio is not present for about 1 second. Thus unfortunately precludes its use for live work doesn't it, which is a real shame. Setting Bypass to either DSP or relay makes no difference and I do have 2.4.1 installed.