I thought that in the current models (the Trezor 1 and the Trezor Model T), whether it is bitcoin ONLY or multi-coin is a kind of a software setup. So when you initially set up the device, you can choose whether to set up for bitcoin only or for multi-coin.. and if you want to change back to the other, then you have to erase the device and start over.
Or maybe I am wrong.. in the older devices it is firm ware, but the firmware can still be changed back and forth, no?
That's exactly how it is with the older versions. During the onboarding stage, you need to pick between the Bitcoin-only and multi-coin firmware. And you can, of course, reset the device at anytime and install the other firmware.
So now, in the newer version, there is a kind of difference in the hardware that the consumer has to choose which one and cannot elect how to set it up after receiving it?
I don't think there is any difference hardware-wise. The difference is in the design of the case. Trezor released two different cases. The universal model is black, front and back. The limited Bitcoin-only version (that is already sold out) comes with an orange back cover and inscription saying
21 million or something like that. But I think both of them support both types of firmware.