I have uploaded the grbl code to 2 different arduinos and both time it works successfully, when i open the serial monitor i get the prompt but i cannot type anything. Thus i cant access the help message. (i am english, in england so $ is the upercase of the 4 button if that has anything to do with it)
It seems not-a-lot of tinyG types are also active on gshields and grbl.
Unless you are experimenting with G2, this item is probably better posted in the