Thanks for replying.
The kb stops completely to work, but tt wasn’t freezed. I tryed to plug/unplug several times but didn’t help, I tried a lot of random key bindings strokes but the kb did stay as dead, i.e. the leds for caps lock etc didn’t work anymore, it was as the kb itself was freezed.
On tt, nothing really intensive for what I remember, but - you know - I’m a 10 days old babe, I’m experimenting a lot trying to scratch the surface of this overwhelming rabbit hole, so maybe I’ve done something intensive without the intention. So kb was freezed until the next power cycle.
The bright side is this is never happened anymore until now, even with super fast metro, stupid and intricate scripts, and so on.
No grid here, and unfortunately no alternative kb.
But I think maybe it will be nice to have some strategy from onboard to save presets without a kb.
Maybe also a way to power cycle without to have the whole power bus going on / off would be nice, but maybe a little dangerous, I don’t know… Just random thoughts 
EDIT: the 3 leds on kb don’t work at all when plugged on tt, even on normal behaviour, so I don’t know if actually kb was freezed