lifetime service via transplanting chips

I hope this is not "taboo" here I understand if it is. i was wondering what chip does the subscription live in because i am considering buying on ebay 2 tivo motherboards from lifetime subscribed tivos that the power supplies and/or har d drives had failed and taking a soldering iron to the motherboards and my 2 tivos and swap the chips to get lifetime service on my box.

i was wondering too would that cause the hard drive not to work because it would see the drive as coming from another box too?

thanks and i am sorry if this is a banned subject.