The hardware signing is not enough for transaction to be accepted. User signing is also required. You need two signatures, that are linked to each other. As fo

The hardware signing is not enough for transaction to be accepted. User signing is also required. You need two signatures, that are linked to each other. As for IDs, this is the right question :) You are not allowed to have gaps in transactions counter. You have to submit all of them to the network. Sure, you can have some transmission failure due to broken connection or computer failure. For such case a device can have memory of signed transactions (at least recent ones) and re-transmit them until they reach the network.