Upgraded my i5 ThinkPad X220 with an i7 motherboard bought on eBay. Think I figured out why ethernet is the only thing that doesn't work : r/techsupportgore
MSI B250M PRO OPT BOOST Desktop Motherboard- MS-7A74 | eBay
ASUS Prime Intel H510 LGA 1200 Micro ATX Motherboard for sale online | eBay
Intel D5400XS LGA771 Motherboard w 2 QX9775 intel CPU & Fans Used Tested | eBay