Hi! Since firmware update 3.5 I've "accidently" found a way to manage inputs 1 & 2 with more flexibility on my HX Stomp, not a perfect solution but very useful for me.
The solution : Start with the new STEREO IR BLOCK right at the beginning of your chain, with EMPTY IRs SLOTS
Cons : it uses one block and you can't add any other IR then in your chain :/ (looks like the HX Stomp is limited to 2 IRs max)
Pros : in the stereo IR block parameters you can do whatever you want with setting up independent input 1 and 2 levels, panning, and polarity. So if you have both input 1 and 2 plugged in (I'm not using the HX Stomp as a USB interface but I assume this would also work there, to be confirmed if you have any feedback) then the signal at the beginning of the chain is stuck to stereo L (input 1) / R (input2) but you can mute input 1 or 2 per preset by setting respectively IR A level or IR B level to its minimum value, plus you can pan the remaining signal at the center if you want (adding any mono block afterwards also does the trick) so that you finally have a preset with a single input signal centered while still having something plugged to the second input, and you can still do A/B path splitting afterwards in your preset if you want to!
Note : the fact that the stereo IR block is set with empty IR slots means the 2 input signals are left untouched, so in fact the new stereo IR block found in firmware 3.5 is hacked here to become a flexible stereo input management block.
Of course Line6 should definitely provide with that same flexibility directly inside the input block and per preset, that would make far more sense ( next firmware update please ! =) )
Regards,
Matthieu