Hello,
I bought my Trezor online some years back. (it's the original not the new one)

For a long time I have been worrying - what if the seller, tampered with it before sending it to me.
 {it was an authorized seller~ from memory}

I've never stored much crypto on it due to this concern. While I've not had any problems so far, I also haven't put enough worth stealing on it yet.
------

Is this a valid worry, is it technically possible to receive a device with the equivalent of a key-logger or something in it? Or maybe a pre-made duplicate ?
I seem to remember that when you use the device for the first time - it generates a new and unique set of mnemonic passwords - to transfer ownership of the device.
So surely someone else couldn't have access to these backup pharses/mnemomics unless they had physical access to my device/menomic phrases? As they were created; after I created them, and weren't present before I hit the 'create' button..{or started it for the first time e.t.c}

Just getting a bit paranoid...
Would re-booting resetting my Trezor to default and starting with a new set of mnemomics remove any chance of the above?  

Thanks.
TG